Download EMC VSPEX WITH EMC XTREMSF AND EMC XTREMCACHE EMC VSPEX

DESIGN GUIDE
EMC VSPEX WITH EMC XTREMSF AND
EMC XTREMCACHE
EMC VSPEX
Abstract
This Design Guide describes how to use EMC® XtremSF™ and EMC XtremCache™ in a
virtualized environment with an EMC VSPEX™ Proven Infrastructure for VMware
vSphere or Microsoft Hyper-V. This Design Guide also illustrates how to configure
XtremSF, allocate XtremCache resources following best practices for maximum
effectiveness, and use all the benefits that XtremCache offers.
December 2013
Copyright © 2013 EMC Corporation. All rights reserved. Published in the USA.
Published December 2013.
EMC believes the information in this publication is accurate as of its publication date.
The information is subject to change without notice.
The information in this publication is provided as is. EMC Corporation makes no
representations or warranties of any kind with respect to the information in this
publication, and specifically disclaims implied warranties of merchantability or
fitness for a particular purpose. Use, copying, and distribution of any EMC software
described in this publication requires an applicable software license.
EMC2, EMC, and the EMC logo are registered trademarks or trademarks of EMC
Corporation in the United States and other countries. All other trademarks used
herein are the property of their respective owners.
For the most up-to-date listing of EMC product names, see EMC Corporation
Trademarks on EMC.com.
EMC VSPEX with EMC XtremSF and EMC XtremCache
Design Guide
Part Number H12565
2
EMC VSPEX with EMC XtremSF and EMC XtremCache
Design Guide
Contents
Contents
Chapter 1
Introduction
9
Purpose ............................................................................................................... 10
Business value ..................................................................................................... 10
Scope .................................................................................................................. 10
Audience.............................................................................................................. 11
Terminology ......................................................................................................... 11
Chapter 2
Before You Start
13
Deployment workflow overview ............................................................................. 14
Essential reading .................................................................................................. 14
VSPEX Solution Overviews ................................................................................ 14
VSPEX Implementation Guides.......................................................................... 14
VSPEX Proven Infrastructures ............................................................................ 15
Chapter 3
Solution Overview
17
Introduction ......................................................................................................... 18
EMC VSPEX Proven Infrastructure........................................................................... 18
EMC XtremCache: The business case ..................................................................... 19
XtremSF and XtremCache ...................................................................................... 20
XtremSF ........................................................................................................... 20
XtremCache ..................................................................................................... 20
Business benefits of XtremSF and XtremCache ....................................................... 21
XtremSF ........................................................................................................... 21
XtremCache ..................................................................................................... 21
XtremCache features............................................................................................. 22
XtremCache management................................................................................. 28
VNX integration ................................................................................................ 30
Oracle RAC support .......................................................................................... 30
Software-only feature ....................................................................................... 31
AIX support ...................................................................................................... 31
Solution architecture ............................................................................................ 32
How XtremCache works .................................................................................... 32
XtremCache in a virtualized environment........................................................... 35
EMC VSPEX with EMC XtremSF and EMC XtremCache
Design Guide
3
Contents
Chapter 4
Solution Design Considerations and Best Practices
39
Overview .............................................................................................................. 40
XtremCache Performance Predictor ........................................................................ 40
Requirements .................................................................................................. 40
Sample output from XtremCache Performance Predictor ..................................... 41
VSPEX environments that can benefit from XtremCache .......................................... 44
Selecting an XtremSF card ..................................................................................... 46
Design best practices ....................................................................................... 46
MLC versus SLC................................................................................................ 46
Virtualization design considerations ...................................................................... 47
Sizing recommendations .................................................................................. 47
Performance recommendations ........................................................................ 48
XtremCache placement considerations .................................................................. 48
Flexibility ......................................................................................................... 48
Design best practices ....................................................................................... 48
VMware considerations......................................................................................... 50
Hyper-V considerations ......................................................................................... 52
Chapter 5
XtremCache Solution for Applications
54
Overview .............................................................................................................. 55
Architecture of XtremCache deployment on VMware ............................................... 55
Architecture of XtremCache deployment on Hyper-V ............................................... 57
XtremCache for SQL Server OLTP database ............................................................. 58
Benefits of XtremCache in a SQL Server OLTP environment ................................. 58
Best practices .................................................................................................. 59
Use case design and deployment...................................................................... 59
Configuration of XtremCache in the VMware environment................................... 61
Test results ...................................................................................................... 61
XtremCache for Exchange Server ........................................................................... 63
Benefits of XtremCache in an Exchange environment ......................................... 63
Best practices .................................................................................................. 64
Use case design and deployment...................................................................... 65
Configuration of XtremCache in the VMware environment................................... 67
Test results ...................................................................................................... 70
XtremCache for SharePoint.................................................................................... 74
Benefits of XtremCache in a SharePoint environment ......................................... 74
Best practices .................................................................................................. 74
Use case design and deployment...................................................................... 75
Configuration of XtremCache in the VMware environment................................... 77
4
EMC VSPEX with EMC XtremSF and EMC XtremCache
Design Guide
Contents
Test results ...................................................................................................... 77
XtremCache for Oracle OLTP database ................................................................... 79
Benefits of XtremCache in an Oracle environment .............................................. 79
Best practices .................................................................................................. 79
Use case design and deployment...................................................................... 79
Test results ...................................................................................................... 81
XtremCache for private cloud ................................................................................ 82
Benefits of XtremCache in a private cloud environment ...................................... 83
Best practices .................................................................................................. 83
Use case design and deployment...................................................................... 84
Configuration of XtremCache in the VMware environment................................... 86
Test results ...................................................................................................... 86
Chapter 6
References
90
EMC documentation ............................................................................................. 91
Other documentation ............................................................................................ 92
Links.................................................................................................................... 92
Appendix A Ordering Information
94
Ordering XtremSF and XtremCache ........................................................................ 95
EMC VSPEX with EMC XtremSF and EMC XtremCache
Design Guide
5
Contents
Figures
6
Figure 1.
VSPEX Proven Infrastructure .............................................................. 18
Figure 2.
I/O gap between the processor and storage subsystems .................... 19
Figure 3.
VMware live migration ...................................................................... 23
Figure 4.
XtremCache data deduplication ........................................................ 24
Figure 5.
XtremCache data deduplication architecture overview ........................ 25
Figure 6.
Split-card mode used for SQL Server configuration ............................. 27
Figure 7.
XtremCache Management Center....................................................... 29
Figure 8.
XtremCache deployment in an Oracle RAC environment ...................... 31
Figure 9.
Read Hit example with XtremCache ................................................... 32
Figure 10.
Read Miss example with XtremCache................................................. 33
Figure 11.
Write example with XtremCache ........................................................ 34
Figure 12.
XtremCache implementation in a VMware environment ...................... 35
Figure 13.
XtremCache in a VMware environment ............................................... 36
Figure 14.
XtremCache in a Hyper-V environment ............................................... 37
Figure 15.
XtremCache Performance Predictor sample output: collecting
performance data ............................................................................. 41
Figure 16.
XtremCache Performance Predictor sample output: I/O size
distribution ..................................................................................... 42
Figure 17.
XtremCache Performance Predictor sample output: predicting
the cache hit rate ............................................................................. 43
Figure 18.
XtremCache Performance Predictor sample output: disk latency
prediction ........................................................................................ 44
Figure 19.
XtremCache use cases ...................................................................... 45
Figure 20.
Comparison between SLC and MLC flash cell data storage .................. 46
Figure 21.
Cache device configuration screen .................................................... 50
Figure 22.
XtremCache configuration using EMC VSI plug-in ............................... 51
Figure 23.
XtremCache implementation in VMware environment for VSPEX .......... 51
Figure 24.
XtremCache implementation in Hyper-V environment for VSPEX .......... 53
Figure 25.
Architecture of the VSPEX Proven Infrastructure for XtremCache
deployment on VMware .................................................................... 56
Figure 26.
Architecture of the VSPEX Proven Infrastructure for XtremCache
deployment on Hyper-V .................................................................... 57
Figure 27.
Architecture design for XtremCache enabled SQL Server virtual
environment..................................................................................... 60
Figure 28.
SQL Server AlwaysOn XtremCache deployment .................................. 61
Figure 29.
Performance boost after enabling XtremCache ................................... 62
Figure 30.
Architecture design for XtremCache-enabled Exchange virtual
environment..................................................................................... 66
Figure 31.
XtremCache deployment for Exchange 2010 on vSphere .................... 67
Figure 32.
Enabling data deduplication on the XtremCache device ...................... 68
EMC VSPEX with EMC XtremSF and EMC XtremCache
Design Guide
Contents
Figure 33.
Exchange 2010 performance with XtremCache and LoadGen workload 71
Figure 34.
XtremCache statistics with data deduplication ................................... 71
Figure 35.
Exchange server CPU utilization with XtremCache data deduplication . 73
Figure 36.
Exchange server disk latencies with XtremCache data deduplication ... 73
Figure 37.
Exchange database LUN performance with XtremCache data
deduplication................................................................................... 74
Figure 38.
Architecture design for XtremCache enabled SharePoint environment . 76
Figure 39.
XtremCache deployment for SharePoint 2010 on vSphere .................. 77
Figure 40.
Content database latency dropped after enabling XtremCache ........... 78
Figure 41.
Full crawl performance improved after enabling XtremCache .............. 78
Figure 42.
Architecture design for XtremCache enabled Oracle 11 g R2
environment..................................................................................... 80
Figure 43.
XtremCache deployment for Oracle 11g R2 on vSphere ....................... 81
Figure 44.
OLTP TPM improvement .................................................................... 82
Figure 45.
Architecture design for XtremCache-enabled private cloud environment
with multiple applications ................................................................ 85
Figure 46.
Deduplication statistics for SQL Server OLTP ...................................... 87
Tables
Table 1.
Terminology ..................................................................................... 11
Table 2.
Deployment process: XtremSF and XtremCache overlay on
VSPEX Proven Infrastructure .............................................................. 14
Table 3.
Performance characteristics of selected XtremSF cards ....................... 20
Table 4.
XtremSF device card group for cache pool in ESXi environment ........... 26
Table 5.
XtremCache management utilities ..................................................... 28
Table 6.
XtremCache management utilities ..................................................... 29
Table 7.
SLC and MLC flash comparison ......................................................... 47
Table 8.
Recommended cache for each application ......................................... 48
Table 9.
Performance data with OLTP load ...................................................... 63
Table 10.
XtremCache deployment in a private cloud environment..................... 86
Table 11.
Performance summary for the private cloud environment.................... 88
EMC VSPEX with EMC XtremSF and EMC XtremCache
Design Guide
7
Contents
8
EMC VSPEX with EMC XtremSF and EMC XtremCache
Design Guide
Chapter 1: Introduction
Chapter 1
Introduction
This chapter presents the following topics:
Purpose ............................................................................................................... 10
Business value ..................................................................................................... 10
Scope .................................................................................................................. 10
Audience.............................................................................................................. 11
Terminology ......................................................................................................... 11
EMC VSPEX with EMC XtremSF and EMC XtremCache
Design Guide
9
Chapter 1: Introduction
Purpose
EMC® VSPEX™ Proven Infrastructures are optimized for virtualizing business-critical
applications. VSPEX provides partners with the ability to plan and design the virtual
assets to support applications such as Microsoft SQL Server, Microsoft SharePoint,
Microsoft Exchange, and Oracle Database on a VSPEX private cloud.
The EMC VSPEX with EMC XtremSF™ and EMC XtremCache™ solution provides
partners with a server-based caching solution that reduces application latency and
increases throughput. This solution runs on a VMware vSphere or Microsoft Hyper-V
virtualization layer, backed by the highly available EMC VNX ® family of storage
systems. The computing and network components, while vendor-definable, are
designed to be redundant and are sufficiently powerful to handle the processing and
data needs of the virtual machine environment.
This design guide describes how to select and configure XtremCache resources for a
VSPEX Proven Infrastructure and includes best practices and the results of use case
testing.
Business value
IT administrators are often challenged to improve the performance of applications
running heavy input/output (I/O) loads, while continuing to minimize the cost of the
supporting systems. These I/O sensitive applications are typically limited by storage
latency and response times. XtremCache is intelligent caching software that uses
server-based flash technology to improve performance by reducing latency and
accelerating throughput for dramatic application performance improvement.
XtremCache accelerates read performance by putting the data closer to the
application. It also protects data by using a write-through cache to the networked
storage array to deliver persistent high availability (HA), integrity, and disaster
recovery. XtremCache, coupled with array-based EMC FAST™ software, creates the
most efficient and intelligent I/O path from the application to the datastore. The
result is a networked infrastructure that is dynamically optimized for performance,
intelligence, and protection for both physical and virtual environments.
Scope
This design guide is an overlay solution that describes how to select and deploy
XtremCache resources on a VSPEX Proven Infrastructure for VMware vSphere or
Microsoft Hyper-V. Furthermore, this guide illustrates best practices and
recommendations for using XtremCache to improve the performance of virtualized
applications running on a VSPEX Proven Infrastructure.
10
EMC VSPEX with EMC XtremSF and EMC XtremCache
Design Guide
Chapter 1: Introduction
Audience
This guide is intended for qualified EMC VSPEX partners. The guide assumes that
VSPEX partners who intend to deploy XtremSF and XtremCache on respective
applications are:

Qualified to sell and implement the application(s) that will be used in
conjunction with the XtremCache solution

Qualified by EMC to sell, install, and configure the EMC VNX family of storage
systems

Certified for selling VSPEX Proven Infrastructures

Qualified to sell, install, and configure the network and server products
required for VSPEX Proven Infrastructures

Trained in and familiar with EMC’s XtremSF hardware and XtremCache software
Readers must also have the necessary technical training and background to install
and configure:

EMC VSPEX private cloud solutions for VMware vSphere or Microsoft Hyper-V,
depending on the hypervisor in use

Windows Server 2012 with Hyper-V or VMware vSphere as the virtualization
platforms
External references are provided where applicable and EMC recommends that readers
become familiar with these documents. For details, see Essential reading.
Terminology
Table 1 includes the terminology used in this guide.
Table 1.
Terminology
Term
Definition
Cache page size
The smallest unit of allocation that is inside the cache, typically a few
kilobytes in size. The default XtremCache page size is 8 KB.
CSV
Cluster-shared volume. A Windows Server clustering feature that
enables multiple clustered virtual machines to use the same logical
unit number (LUN).
DAS
Direct-attached storage
DSS
Decision support system
IOPS
Input/output operations per second
MLC
Multi-level cell flash. A flash memory technology using multiple
levels per cell to allow more bits to be stored using the same number
of transistors.
NFS
Network File System
EMC VSPEX with EMC XtremSF and EMC XtremCache
Design Guide
11
Chapter 1: Introduction
12
Term
Definition
PCIe
Peripheral Component Interconnect Express
SLC
Single-level cell flash. A type of solid-state storage (SSD) that stores
one bit of information per cell of flash media.
tempdb
Refers to a system database used by Microsoft SQL Server as a
temporary working area during processing.
VHDX
Hyper-V virtual hard disk format
VMDK
VMware virtual machine disk format
Working set
The frequently accessed data that is likely to be promoted to
XtremCache
XtremCache
EMC server flash-caching software
XtremSF
EMC Peripheral Component Interconnect Express (PCIe) Flash cards
with industry-leading performance
EMC VSPEX with EMC XtremSF and EMC XtremCache
Design Guide
Chapter 2: Before You Start
Chapter 2
Before You Start
This chapter presents the following topics:
Deployment workflow overview............................................................................. 14
Essential reading ................................................................................................. 14
EMC VSPEX with EMC XtremSF and EMC XtremCache
Design Guide
13
Chapter 2: Before You Start
Deployment workflow overview
EMC recommends that you refer to the process flow in Table 2 to design and
implement your XtremSF and XtremCache overlay on the VSPEX Proven Infrastructure.
Table 2.
Deployment process: XtremSF and XtremCache overlay on VSPEX Proven
Infrastructure
Step
Action
Reference
1
Review the Xtrem products and features.
EMC documentation
2
Determine if the XtremCache solution is
appropriate for your application.
Solution Design
Considerations and Best
Practices
3
Select and order the right VSPEX Proven
Infrastructure.
VSPEX Proven
Infrastructures
4
Select the required XtremCache hardware and
determine where to place the cards.
XtremCache Solution for
Applications
5
Deploy and test your virtualized applications.
VSPEX Implementation
Guides
Essential reading
EMC recommends that you read the following documents, available from the VSPEX
space in the EMC Community Network or from the VSPEX Enablement Center.
VSPEX Solution
Overviews
VSPEX
Implementation
Guides
14
Refer to the following VSPEX Solution Overview documents:

EMC VSPEX Server Virtualization for Midmarket Businesses

EMC VSPEX Server Virtualization for Small and Medium Businesses
Refer to the following VSPEX Implementation Guides:

EMC VSPEX for Virtualized Microsoft Exchange 2010 with Microsoft Hyper-V

EMC VSPEX for Virtualized Microsoft Exchange 2010 with VMware vSphere

EMC VSPEX for Virtualized Microsoft Exchange 2013 with Microsoft Hyper-V

EMC VSPEX for Virtualized Microsoft Exchange 2013 with VMware vSphere

EMC VSPEX for Virtualized Microsoft SharePoint 2010 with Microsoft Hyper-V

EMC VSPEX for Virtualized Microsoft SharePoint 2010 with VMware vSphere

EMC VSPEX for Virtualized Microsoft SharePoint 2013 with Microsoft Hyper-V

EMC VSPEX for Virtualized Microsoft SharePoint 2013 with VMware vSphere

EMC VSPEX for Virtualized Microsoft SQL Server 2012 with Microsoft Hyper-V

EMC VSPEX for Virtualized Microsoft SQL Server 2012 with VMware vSphere
EMC VSPEX with EMC XtremSF and EMC XtremCache
Design Guide
Chapter 2: Before You Start

VSPEX Proven
Infrastructures
EMC VSPEX for Virtualized Oracle Database 11g OLTP
Refer to the following VSPEX Proven Infrastructures:

EMC VSPEX Private Cloud VMware vSphere 5.1 for up to 100 Virtual Machines

EMC VSPEX Private Cloud VMware vSphere 5.1 for up to 500 Virtual Machines

EMC VSPEX Private Cloud VMware vSphere 5.1 for up to 1,000 Virtual Machines

EMC VSPEX Private Cloud VMware vSphere 5.5 for up to 1,000 Virtual Machines

EMC VSPEX Private Cloud Microsoft Windows Server 2012 with Hyper-V for up to
100 Virtual Machines

EMC VSPEX Private Cloud Microsoft Windows Server 2012 with Hyper-V for up to
500 Virtual Machines

EMC VSPEX Private Cloud Microsoft Windows Server 2012 with Hyper-V for up to
1,000 Virtual Machines
EMC VSPEX with EMC XtremSF and EMC XtremCache
Design Guide
15
Chapter 2: Before You Start
16
EMC VSPEX with EMC XtremSF and EMC XtremCache
Design Guide
Chapter 3: Solution Overview
Chapter 3
Solution Overview
This chapter presents the following topics:
Introduction ......................................................................................................... 18
EMC VSPEX Proven Infrastructure.......................................................................... 18
EMC XtremCache: The business case..................................................................... 19
XtremSF and XtremCache...................................................................................... 20
Business benefits of XtremSF and XtremCache ...................................................... 21
XtremCache features ............................................................................................ 22
Solution architecture............................................................................................ 32
EMC VSPEX with EMC XtremSF and EMC XtremCache
Design Guide
17
Chapter 3: Solution Overview
Introduction
This design guide describes the requirements and process for deploying EMC XtremSF
and XtremCache on VSPEX Proven Infrastructures. The guidance applies to all VSPEX
Proven Infrastructures unless specifically stated otherwise.
This chapter provides an overview of VSPEX Proven Infrastructure, XtremSF and
XtremCache, and the key technologies used in the XtremSF and XtremCache overlay
for the VSPEX Proven Infrastructure. A VSPEX Proven Infrastructure includes servers,
storage, network components, and application components that focus on small and
medium business private cloud environments. The XtremSF and XtremCache overlay
provides latency reduction and accelerates throughput for dramatic application
performance improvement.
EMC VSPEX Proven Infrastructure
A VSPEX Proven Infrastructure, as shown in Figure 1, is a modular, virtualized
infrastructure validated by EMC and delivered by EMC partners. VSPEX includes
components supporting virtualization, servers, network, storage, and backup
designed by EMC to deliver reliable and predictable performance. VSPEX enables
businesses to transform their IT, application and end user computing environments
by providing complete virtualization solutions that have been sized and tested by
EMC.
Figure 1.
VSPEX Proven Infrastructure
VSPEX provides the flexibility to choose network, server, and virtualization
technologies that fit a customer’s environment to create a complete virtualization
solution. VSPEX delivers faster deployment for EMC partner customers, with greater
simplicity and efficiency, more choice, and lower risk to a customer’s business.
18
EMC VSPEX with EMC XtremSF and EMC XtremCache
Design Guide
Chapter 3: Solution Overview
EMC XtremCache: The business case
The capabilities of modern processors continue to widen the performance gap
between CPUs and disks. Often, the disk datastore becomes a bottleneck in any
deployed solution.
As processing capacity and workloads increase, the storage system is challenged to
keep pace with growing I/O demands. The performance of the magnetic disk remains
relatively flat while CPU performance improves 100-fold every decade, as shown in
Figure 2. XtremSF Flash drives can help to close the gap.
Figure 2.
I/O gap between the processor and storage subsystems
Flash technology can be used in different ways in the storage environment to
compensate for the performance limitations of disk based storage. EMC’s
architectural approach is to use the right technology in the right place at the right
time. This includes using flash in the following ways:

In the storage array

As an array-side cache

As a server-side cache

As a tier

As the storage for the entire application
EMC VSPEX with EMC XtremSF and EMC XtremCache
Design Guide
19
Chapter 3: Solution Overview
XtremSF and XtremCache
XtremCache (formerly known as VFCache or EMC XtremSW Cache) is the first step in
EMC’s long-term server flash strategy. This strategy delivers a server-side storage
product featuring a combination of intelligent caching software—XtremCache—and
server-based Peripheral Component Interconnect Express (PCIe) Flash hardware—
XtremSF.
XtremCache software turns the XtremSF card into a caching device, to enhance the
performance of a wide variety of critical transactional and decision support
applications. XtremCache can run with a wide variety of multilevel cell (MLC) and
single-level cell (SLC) XtremSF Flash cards.
VSPEX partners can order XtremCache software and XtremSF hardware through
Channel Express. For ordering information, refer to Appendix A: Ordering Information.
XtremSF
XtremCache
XtremSF is single, low-profile server flash hardware card that fits in any rack-mounted
server within the power envelope of a single PCIe slot, and is available with a broad
set of MLC and SLC capacities. It can be deployed:

As local storage that sits within the server to deliver high performance

In combination with XtremCache software to improve network storage array
performance, while maintaining the level of protection required by critical
application environments
You can use EMC XtremCache software to create server-side cache for data.
XtremCache is designed with the following basic principles:

Performance: Reduce latency and increase throughput to dramatically improve
application performance.

Intelligence: Add another tier of intelligence by extending FAST array-based
technology into the server.

Protection: Deliver performance with protection by using the high availability
and disaster recovery features of EMC networked storage.
Table 3 shows the performance characteristics of some selected XtremSF cards.
Table 3.
20
Performance characteristics of selected XtremSF cards
350 GB
MLC
550 GB
MLC
700 GB
MLC
1.4 TB
MLC
2.2 TB
MLC
350 GB
SLC
700 GB
SLC
Read Bandwidth
(MB/s)
3,175
1,555
3,215
3,215
2,600
3,215
3,215
Write Bandwidth
(MB/s)
330
512
570
605
1,000
756
1900
Random 4 K
Read IOPS
730 K
175 K
750 K
750 K
340 K
715 K
750 K
EMC VSPEX with EMC XtremSF and EMC XtremCache
Design Guide
Chapter 3: Solution Overview
350 GB
MLC
550 GB
MLC
700 GB
MLC
1.4 TB
MLC
2.2 TB
MLC
350 GB
SLC
700 GB
SLC
Random 4 K
Write IOPS
23 K
50 K
50 K
95 K
110 K
95 K
205 K
Random 4 K
Mixed IOPS
105 K
110 K
190 K
200 K
220 K
415 K
415 K
Read Access
Latency (4 kB)
μs
100
76
100
100
76
50
50
Write Access
Latency (4 kB) μs
13
30
13
13
30
13
13
Business benefits of XtremSF and XtremCache
XtremSF
XtremCache
XtremSF delivers extremely high performance with low latency and enables
applications to achieve memory-class based performance. It eliminates the need for
additional memory or storage capacity purchases, and thereby helps reduce overall
deployment footprint. The XtremSF family of server-based PCIe Flash cards offers
customers the following benefits:

Leading performance: XtremSF Flash devices are proven to deliver a record 1.13
million IOPS in a standard form factor—an achievement unmatched in the
industry. The XtremSF device’s next-generation design delivers twice the
throughput of other offerings in the market to enhance real world workloads in
Web-scale and other applications.

Unmatched flexibility: The XtremSF Flash device is available in a broad range of
eMLC (from 350 GB up to 2.2 TB) and SLC (350 GB and 700 GB) capacities. In
addition, when deployed with XtremCache, XtremSF devices can be used as
caching devices for accelerated performance with array protection for
applications such as Oracle, Microsoft SQL Server, and Microsoft Exchange.

New levels of efficiency: XtremSF Flash devices deliver the industry’s lowest
total cost of ownership (TCO)—up to 58 percent better TCO than other offerings.
All XtremSF products are standard half-height, half-length, 25W PCIe cards,
providing the highest storage capacity with the smallest footprint for maximum
performance, best density, and lowest power consumption, reducing CPU
utilization by up to 50 percent.
XtremCache delivers the following major benefits:

Provides performance acceleration for read-intensive workloads

As a write-through cache, enables accelerated performance with the protection
of the back-end, networked storage array

Provides an intelligent path for the I/O and ensures that the right data is in the
right place at the right time
EMC VSPEX with EMC XtremSF and EMC XtremCache
Design Guide
21
Chapter 3: Solution Overview

In split-card mode, enables you to use part of the server flash for cache and the
other part as DAS for temporary data

By offloading flash and wear-level management onto the PCIe card, uses
minimal CPU and memory resources from the server

Achieves greater economic value when data deduplication is enabled by
providing an effective cache size larger than the physical size, and longer card
life expectancy

Works in both physical and virtual environments

Integrated with EMC Virtual Storage Integrator (VSI) plug-ins for vSphere makes
it simple to manage and monitor XtremCache in a VMware environment

Works in active/passive clustering environments

Works with VMware live migration

Provides a highly scalable performance model in the storage environment
XtremCache features
Server-side flash
caching for
maximum speed
XtremCache software caches the most frequently referenced data on the server-based
PCIe card XtremSF, thereby putting the data closer to the application.
Write-through
caching for total
protection
XtremCache accelerates reads and protects data by using a write-through cache to
the storage array to deliver persistent high availability, integrity, and disaster
recovery.
Application and
storage agnostic
XtremCache is transparent to applications, so no rewriting, retesting, or recertification
is required to deploy XtremCache in the environment.
The XtremCache caching optimization automatically adapts to changing workloads by
determining the most frequently referenced data and promoting it to the server flash
cache. This means that the “hottest” (most active) data automatically resides on the
PCIe card in the server for faster access.
XtremCache works with any storage array in the enviornment. Regardless of the
vendor or type of the storage, it works seamlessly to improve the performance of the
storage array.
XtremCache offloads much of the read traffic from the storage array, which allows it to
allocate greater processing power to other applications. While one application is
accelerated with XtremCache, the array’s performance for other applications is
maintained or even slightly enhanced.
XtremCache
vSphere
integration
22
XtremCache enhances both virtualized and physical environments. Integration with
VSI plug-ins for vSphere makes it simple to manage and monitor XtremCache.
EMC VSPEX with EMC XtremSF and EMC XtremCache
Design Guide
Chapter 3: Solution Overview
VMware automated live migration
XtremCache supports live virtual machine migration (vMotion), HA, DRS, and SRM.
You can continue to use these technologies exactly as they are used without the
presence of XtremCache.
During the migration process, the virtual machine is operational and the cache is
purged with a temporary I/O performance impact.
XtremCache software must be installed on the virtual machines and the ESX host. The
XtremCache device is created as a RDM device in the XtremCache pool, and passes
through to the assigned virtual machine. The cache device appears to the source and
target ESX hosts as shared resources with a multipath plug-in (MPP) over RDM.
On each virtual machine, a virtual SCSI device is created with a fixed ID. This ID is the
same on all ESX hosts within the cluster. The virtual machine accesses the flash
device using an RDM disk over that SCSI device. Write activity to the cache flows
through the RDM disk to the MPP on the ESX server and from there it flows straight to
the flash device.
Figure 3 illustrates the live migration with XtremCache.
Figure 3.
VMware live migration
Post migration
After the migration, the cache, which always starts cold, must “warm up” again
because the virtual machine now uses a new physical device. This warm-up process
also prevents data on the source device from becoming out of sync with the cached
data. The migrated virtual machine can then follow the HA/DRS policies without any
problems regardless of the XtremCache availability on the new ESXi server.
Integration with
Hyper-V
XtremCache works seamlessly with the Windows Hyper-V host and the virtual
machines that are deployed from it.
EMC VSPEX with EMC XtremSF and EMC XtremCache
Design Guide
23
Chapter 3: Solution Overview
Minimum impact
on system
resources
XtremCache does not require a significant amount of memory or CPU cycles because
all flash and wear-level management is done on the PCIe card and—unlike other PCIe
solutions—does not use server resources.
XtremCache creates the most efficient and intelligent I/O path from the application to
the datastore, which results in an infrastructure that is dynamically optimized for
performance, intelligence, and protection for both physical and virtual environments.
Data deduplication Currently, EMC is the only vendor to provide customers with a deduplication option
on a server cache flash card. Deduplication can provide the following benefits:

Better cost per gigabyte: Using an effective cache size that is larger than the
physical cache size

Longer card life expectancy: Reduction in the number of write operations to the
flash card resulting in lower wear out
Data deduplication can eliminate redundant data by storing only a single copy of
identical chunks of data, while enabling this data to be referenced. As shown in
Figure 4, when deduplication is enabled, only one copy of data is actually stored in
XtremCache. With some additional memory space for pointers, the amount of data
that can be cached increases dramatically.
Figure 4.
XtremCache data deduplication
Data deduplication uses server memory to process the deduplication function and
maximize the capacity of XtremCache. You can enable or disable this function as
needed. Figure 5 shows the deduplication architecture in XtremCache.
24
EMC VSPEX with EMC XtremSF and EMC XtremCache
Design Guide
Chapter 3: Solution Overview
Figure 5.
Active/passive
clustering support
XtremCache data deduplication architecture overview
XtremCache supports several common types of active/passive native operating
system clustering.
Supported active/passive clustering
Some environments (RHEL Cluster Suite, Veritas Cluster Server, and AIX PowerHA)
require configuring the supplied XtremCache Clustering script to ensure that stale
data is never retrieved. The scripts use Cluster Management events that relate to an
application service start/stop transition to trigger a mechanism that purges the
cache. Other environments, such as Microsoft Cluster Service and Oracle Real
Application Clusters, do not require script configuration.
Note: When you use XtremCache in a cluster, do note define quorum disks as source
devices.
Microsoft active/passive cluster support
For XtremCache version 2.0 and higher, multiple applications in a cluster can use
XtremCache for Microsoft Cluster Server environments. The required scripts are
automatically installed during XtremCache installation. Cluster resources are
automatically defined when you define a source device.
Microsoft Cluster Service requires the following:

Windows PowerShell must be installed on the cluster nodes. PowerShell is
usually installed by default during a typical Windows installation.
EMC VSPEX with EMC XtremSF and EMC XtremCache
Design Guide
25
Chapter 3: Solution Overview

The XtremCache driver must be installed on all nodes in the cluster, including
nodes without any server devices.

Applications and shared disks with dependencies must be defined before you
add or start the XtremCache source device. Resources will appear automatically
in the Microsoft Cluster Services (MSCS) window after sources are defined.
In Microsoft active/passive clusters, when the passive node of one cluster is also
configured as the active node of another database cluster, XtremCache supports that
configuration by specifying different XtremCache devices for the two different clusters
on two different nodes.
Multiple cards per
server
You can install Multiple XtremSF cards on a single server and configure them as cache
devices to improve application performance.
XtremCache pool in an ESXi server
In VMware environments, each ESXi server can have one or more XtremCache pools.
You can add devices from a specific vendor and model to the same cache pool.
You can use a flash card in ESXi environments for DAS or for caching, but not for both
(split-card). When you add cards to the local cache pool, all cards from the same
group are added according to those defined in Table 4:
Table 4.
XtremSF device card group for cache pool in ESXi environment
XtremSF device name
XtremSF550
XtremSF2200
XtremSF300S
Member of group
Group A
Group B
XtremSF700
XtremSF1400
XtremSF350S
Group C
XtremSF700S
Using flash cards for DAS
If you use a flash card for DAS, any card used from the same group will be used as the
DAS-intended card and will not be used for caching. For example:
26

For an ESX host on which XtremSF550 and XtremSF2200 are installed, if both
cards are from the same group, both cards must be used for caching or both
cards must be used for DAS.

For an ESX host on which XtremSF550 and XtremSF700 are installed, if the
cards are from different groups, the cards can be used in any combination of
caching and DAS with no limitations.
EMC VSPEX with EMC XtremSF and EMC XtremCache
Design Guide
Chapter 3: Solution Overview
Split-card mode
support
XtremCache includes a unique software option that enables you to split the XtremSF
card between the cache and the local storage. You can simultaneously use the card
as a caching device for critical data, both as a read and as a write storage device for
temporary data. You can fully optimize your workload by adjusting caching or storage
without having to change your card deployment.
With this feature, both read and write operations from the application to the local
storage are performed directly on the flash capacity in the server. Since the data on
the local flash storage does not persist in any storage array, it is best used for
ephemeral data only, such as the operating system swap space and temporary file
space.
Figure 6 shows an example of a use case for the split-card mode of XtremCache. In a
SQL Server, where the tempdb needs acceleration for both read and write operations
but the database file only needs read acceleration, XtremSF can be configured so that
part of the card can be used for the local storage as tempdb, and part of it can be
used as a cache. However, there is a limitation in this configuration as vMotion is not
viable when the tempdb storage is local.
Figure 6.
Split-card mode used for SQL Server configuration
EMC VSPEX with EMC XtremSF and EMC XtremCache
Design Guide
27
Chapter 3: Solution Overview
XtremCache
management
XtremCache includes management utilities described in Table 5.
Table 5.
XtremCache management utilities
Management utility
Description
Command Line Interface (CLI)
You can use the CLI to execute vfcmt commands to
configure and manage XtremCache. It is installed with the
XtremCache installation.
VSI Plug-in
The EMC VSI Storage Viewer for VMware vSphere™ (VSI) is
a plug-in to VMware’s vSphere Client that provides a
single management interface used for managing EMC
storage including XtremCache within the vSphere
environment.
Lite Client
Xtrem Lite Client enables you to view, manage, and
monitor the XtremCache of a physical or virtual machine or
ESX host. You can also use Lite Client to manage the
XtremCache of an individual system.
Communication between the Lite Client and managed
systems uses the CIM/XML protocol over HTTPS on the
port 5989.
Management Center
The XtremCache Management Center provides all the
functionality of the Lite Client. In addition, it retains
machine history and enables you to manage multiple
machines (physical, virtual, and ESX hosts) from a single
view.
VNX users can benefit from the integration of the management center with Unisphere
remote for VNX. For VNX LUNs being accelerated by XtremCache, this integration
simplifies the cache performance monitoring by displaying the information directly on
the Unisphere Remote management screens. In addition, you can see the health
information of XtremSF flash cards that are managed by the Management Center from
Unisphere Remote.
To enable this integration, register the XtremCache Management Center in the
Unisphere Remote by providing the IP addresses and credentials of the Management
Center.
28
EMC VSPEX with EMC XtremSF and EMC XtremCache
Design Guide
Chapter 3: Solution Overview
Figure 7 shows the XtremCache Management Center’s performance view.
Figure 7.
XtremCache Management Center
Table 6 shows the differences between the XtremCache management utilities that
you can choose to fit the specific needs of your environment.
Table 6.
XtremCache management utilities
Management
Center
CLI
VSI plug-in
Lite Client
Environment
All
VMware
Physical , except
AIX
All, except AIX
Installation
Installed by default
with caching
software runs on
the server
VMware plug-in for
vSphere Client
Desktop client
installed and runs
on a windows
machine
Run as a virtual
appliance (vApp),
Web interface, no
client installation
Scale
Manages single
machine
Manages multiple
machines
Manages single
machine
Manages multiple
machines
Recommended for
Scripting, when
GUI access isn’t
needed, or for AIX
Management of
multiple
accelerated virtual
machines
GUI access to a
single machine,
with minimal setup
costs
Managing multiple
machines, or when
history and audit
on changes is
important
-
-
External API
-
REST API
EMC VSPEX with EMC XtremSF and EMC XtremCache
Design Guide
29
Chapter 3: Solution Overview
VNX integration
If VNX Unisphere Remote is deployed, XtremCache can be managed and monitored
directly through Unisphere Remote.
Configuration and monitoring, such as link and launch capabilities to drill down and
configure any cache device in the system, can all be done in a single management
panel with:
Oracle RAC
support

LUN selection based on VNX trending analysis

Performance and health monitoring

Discovery and configuration
XtremCache support for Oracle RAC enables active/active shared storage in an Oracle
environment with a distributed cache coherency algorithm. XtremCache supports
Oracle RAC in the following environment:

Oracle 11g on Windows, RHEL, or OEL (running the same OS versions that are
supported by XtremCache)

Running Oracle Clusterware 11g with Ethernet interconnect

Up to eight nodes per cluster
At installation time, XtremCache automatically recognizes the presence of Oracle RAC
and switches operation to clustering mode.
When a certain block of information is overwritten in shared storage and on a cache
device, other cache devices in the cluster will delete that block from their cache
devices to prevent the use of invalid data.
When a node joins the cluster, XtremCache must know about it to provide
modification to shared storage by that node. The integration with the Oracle cluster
management using SCSI-3 Persistent Reservations to notify the back-end storage to
wait until XtremCache “approves” the joining node before accessing the storage.
When a node leaves the cluster, all cache devices will change to pass-through mode
and are purged to ensure coherency.
We recommend using this feature to cache your data file LUNs. Do not use it to cache
redo logs, archives, temporary data, or grid data.
Note: XtremCache is supported in AIX environments, but we do not support XtremCache for
Oracle RAC in AIX environments.
30
EMC VSPEX with EMC XtremSF and EMC XtremCache
Design Guide
Chapter 3: Solution Overview
Figure 8 shows how an Oracle RAC environment deploys XtremCache.
Figure 8.
XtremCache deployment in an Oracle RAC environment
Software-only
feature
XtremCache’s software-only feature enables you to use XtremCache to serve as a
cache device with any other devices. For example, you can use it in blade servers as
well as many other device forms including all SATA or SAS SSD devices and PCIe
cards such as HHHL and HHFl. You can also use devices with SATA, ATA, or SCSi bus
configurations. VMware environments support SCSi devices only.
AIX support
XtremCache versions 2.0 and above support IBM Power 7 servers with AIX 6.1 and
7.1. The standard edition of PowerVM; Native clustering (PowerHA active/passive);
and Certified AIX SSDs are supported as underlying hardware.
EMC VSPEX with EMC XtremSF and EMC XtremCache
Design Guide
31
Chapter 3: Solution Overview
Solution architecture
How XtremCache
works
If the application I/O is for a source volume on which XtremCache has not been
enabled, then the XtremCache driver is transparent to the application I/O and works
as if there is no XtremCache driver in the server I/O stack. In the following examples,
the application I/O is assumed for a source volume which is being accelerated by
XtremCache.
Read Hit example
In this example, XtremCache has been running for some time and the application
working set has already been promoted into XtremCache. The application issues a
read request, and the data is present in XtremCache. This process is called “Read
Hit”, as shown in Figure 9.
Figure 9.
Read Hit example with XtremCache
The sequence of the steps in Figure 9 is:
32
1.
The application issues a read request that is intercepted by the XtremCache
driver.
2.
Because the application working set has already been promoted into
XtremCache, the XtremCache driver determines that the data being requested
by the application already exists in the XtremCache. Therefore, the read
request is sent to the PCIe XtremSF card rather than to the back-end storage.
3.
Data is read from the XtremCache and returned to the application.
EMC VSPEX with EMC XtremSF and EMC XtremCache
Design Guide
Chapter 3: Solution Overview
Read Hit provides the entire throughput and latency benefits of XtremCache to the
application because the read request is fulfilled within the server rather than
incurring latencies by going over the network to the back-end storage.
Read Miss example
In this example, the application issues a read request and the data is not present in
XtremCache. This process is called “Read Miss”, as shown in Figure 10. The data is
not present in XtremCache either because the card has just been installed in the
server or the application working set has changed so that the application has not yet
referenced this data.
Figure 10. Read Miss example with XtremCache
The sequence of the steps in Figure 10 is:
1.
The application issues a read request that is intercepted by the XtremCache
driver.
2.
The XtremCache driver determines that the requested data is not in
XtremCache and forwards the request to the back-end storage.
3.
The data is read from the back-end storage and returned to the application.
4.
Once the application read request is completed, XtremCache driver writes the
requested data to the XtremSF card. This process is called “promotion”. This
means that when the application reads the same data again, it will be a Read
Hit for XtremCache, as described in the previous example.
If all the cache pages in XtremCache are already used, XtremCache uses a leastrecently-used (LRU) algorithm to write new data. If needed, the data that is least likely
to be used in future is discarded first to create space for the new XtremCache
promotions.
EMC VSPEX with EMC XtremSF and EMC XtremCache
Design Guide
33
Chapter 3: Solution Overview
Write example
In this example, the application has issued a write request, as shown in Figure 11.
Figure 11. Write example with XtremCache
The sequence of the steps in Figure 11 is:
1.
The application issues a write request that is intercepted by the XtremCache
driver.
2.
Since this is a write request, the XtremCache driver passes this request to the
back-end storage for completion. The data in the write request is written to
the XtremCache card in parallel.
If the application is writing to a storage area that has already been promoted
to XtremCache, the copy of that data in XtremCache is overwritten. Therefore,
the application does not receive a stale or old version of data from the
XtremCache in response to future read requests. XtremCache algorithms
ensure that, if the application writes some data and then reads the same data
later on, the read requests will find the requested data in XtremCache.
3.
Once the write operation is completed on the back-end storage, an
acknowledgment for the write request is sent back to the application.
The process of promoting new data into XtremCache, as described in the previous two
examples, is called “cache warm-up”. Any cache needs to be warmed up with the
application working set before the application starts seeing the performance
benefits. When the working set of the application changes, the cache automatically
warms up with the new data over a period of time.
34
EMC VSPEX with EMC XtremSF and EMC XtremCache
Design Guide
Chapter 3: Solution Overview
XtremCache in a
virtualized
environment
The implementation of XtremCache in a virtualized environment is slightly different
from an implementation in a physical environment. In a virtualized environment,
multiple virtual machines on the same server may share the performance advantages
of a single XtremSF card or multiple XtremSF cards in the XtremCache pool.
VMware environment
Figure 12 shows an XtremCache implementation in a VMware virtualized
environment.
Figure 12. XtremCache implementation in a VMware environment
An XtremCache implementation in a VMware environment consists of the following
components:

A physical XtremSF card on the VMware ESX Server

XtremSF firmware and driver and XtremCache software on the ESX Server

XtremCache software in each virtual machine that needs to be accelerated
using XtremCache. This includes the XtremCache driver, command line
interface (CLI) package, and XtremCache Agent. Only virtual machines that
need to be accelerated with XtremCache must have XtremCache software
installed.

The Xtrem VSI Plug-in for XtremCache management in the VMware vCenter
client
Both the raw device mapping (RDM) and Virtual Machine File System (VMFS) volumes
are supported with XtremCache. Network File System (NFS) file systems in VMware
environments are supported as well.
EMC VSPEX with EMC XtremSF and EMC XtremCache
Design Guide
35
Chapter 3: Solution Overview
Figure 13 shows implementation details of a VMware environment.
Figure 13. XtremCache in a VMware environment
The flash device appears to the source and target ESXi hosts as a shared resource
through a multipath plug-in (MPP) over RDM. On each virtual machine, a virtual SCSI
device with a fixed ID that is identical over all ESX hosts on the cluster is used to
access the flash device.
XtremCache provides the flexibility to implement its caching capacity for one or many
virtual machines in the ESX host from the vCenter server, with the VSI plug-in or
XtremCache Management Center providing a single view for configuration and
management. To configure this environment:
36

The Xtrem shared datastore (named XtremSW_Cache_DS) must be created on a
LUN that is visible to all ESXi hosts in the datacenter that may host a virtual
machine with XtremCache on it. The LUN does not need to be larger than 1 GB.

Add the XtremSF devices to the ESXi server XtremCache pool. Multiple cards
from the same group (see Table 4) on the same ESXi server will need to be
added to the same cache pool.

Enable XtremCache remote monitoring from VSI plug-in.

Enable UUID mapping to support vMotion, HA, DRS, and SRM to create a cache
device from the XtremCache pool. You can determine the size of the cache
device by the caching requirements of the specific virtual machine.

After creating the cache device, you can use it the way as you use it in the
physical environment.

Attach a source device to be accelerated. Acceleration starts by default.
EMC VSPEX with EMC XtremSF and EMC XtremCache
Design Guide
Chapter 3: Solution Overview
The cache space in the ESX cache pool is only consumed when the virtual machine is
active and there is enough space on that ESX server. vMotion activity will be
successful even if there is no cache or there is not enough space on the ESX server.
The cache space for XtremCache is allocated on a first-come, first-served basis.
If there is no space when the virtual machine is active, the XtremCache operates in
pass-through mode (as if there is no XtremCache) until there is space for it. This
allows vMotion to move the virtual machines to another ESX server even if there is not
enough cache space (or if the cache card has failed for any reason).
Hyper-V environment
Figure 14 shows an implementation in a Hyper-V virtualized environment.
Figure 14. XtremCache in a Hyper-V environment
An XtremCache implementation in a Hyper-V environment consists of the following
components:

A physical XtremSF card on the Windows Hyper-V server

XtremSF driver and firmware on the Windows Hyper-V server

XtremCache software on the Windows Hyper-V server
In a Hyper-V environment, all the devices that need to be accelerated are configured
at the Hyper-V root server level. The installation procedure is identical to the
procedure for the physical Windows server.
Unlike the VMware implementation, all virtual machines in the Hyper-V environment
share the same physical XtremSF card installed on the Hyper-V server. Caching is
provided through the Hyper-V host.
EMC VSPEX with EMC XtremSF and EMC XtremCache
Design Guide
37
Chapter 3: Solution Overview
In the Hyper-V environment, XtremCache provides the caching capacity to support
one or many virtual machines in the Hyper-V host:
38

Virtual disks can be defined either before or after configuring the LUN as a
source device.

All virtual disks allocated on a source device LUN will be accelerated.

NFS, Hyper-V virtual hard disk (VHDX), and physical pass-through disk types are
all supported. Currently, cluster- shared volumes (CSV) are not supported.
EMC VSPEX with EMC XtremSF and EMC XtremCache
Design Guide
Chapter 4: Solution Design Considerations and Best Practices
Chapter 4
Solution Design Considerations and
Best Practices
This chapter presents the following topics:
Overview .............................................................................................................. 40
XtremCache Performance Predictor ....................................................................... 40
VSPEX environments that can benefit from XtremCache ......................................... 44
Selecting an XtremSF card .................................................................................... 46
Virtualization design considerations ..................................................................... 47
XtremCache placement considerations ................................................................. 48
VMware considerations ........................................................................................ 50
Hyper-V considerations ........................................................................................ 52
EMC VSPEX with EMC XtremSF and EMC XtremCache
Design Guide
39
Chapter 4: Solution Design Considerations and Best Practices
Overview
This chapter provides best practices and considerations for the XtremCache
implementation within the VSPEX Proven Infrastructure for various applications. We 1
considered the following aspects during the solution design:

XtremCache Performance Predictor

XtremCache remote management console

XtremSF card selection

XtremCache layout design

Virtualization design
XtremCache Performance Predictor
XtremCache Performance Predictor is a free tool available on EMC Online Support.
You can use this tool to estimate the benefits of implementing XtremCache in a
specific environment. This tool collects data on the host side using common trace
collection tools, and trace analysis on a host or on any laptop that meets the system
requirements. The tool simulates XtremCache’s operations and generates a PDF
output file describing the benefits.
Requirements
This tool requires no card or software purchase and runs on all XtremCachesupported operating systems.
The tool creates a set of charts and graphics that show whether the environment can
benefit from XtremCache, and provides an estimate of possible performance
improvement based on:
1
40

Observed host response time

Capacity used by the host

Skew level
In this guide, “we” refers to the EMC Solutions engineering team that validated the solution.
EMC VSPEX with EMC XtremSF and EMC XtremCache
Design Guide
Chapter 4: Solution Design Considerations and Best Practices
Sample output
from XtremCache
Performance
Predictor
This section provides sample output from the XtremCache Performance Predictor tool.
Figure 15 shows the performance collection and the cache configuration from a
sample PDF output of the tool.
Figure 15. XtremCache Performance Predictor sample output: collecting performance data
EMC VSPEX with EMC XtremSF and EMC XtremCache
Design Guide
41
Chapter 4: Solution Design Considerations and Best Practices
Figure 16 shows the tool’s output regarding the disk I/O distribution. You can use this
information to set the page size and maximum I/O size of the actual XtremCache for
better performance if required (the default for page size is 8 K and maximum I/O size
is 64 k).
Figure 16. XtremCache Performance Predictor sample output: I/O size
distribution
42
EMC VSPEX with EMC XtremSF and EMC XtremCache
Design Guide
Chapter 4: Solution Design Considerations and Best Practices
Figure 17 shows the cache read analysis. If the tool indicates a very high cache hit
rate, then the device under load is a good candidate for XtremCache acceleration.
Figure 17. XtremCache Performance Predictor sample output: predicting the cache hit rate
EMC VSPEX with EMC XtremSF and EMC XtremCache
Design Guide
43
Chapter 4: Solution Design Considerations and Best Practices
Figure 18 shows an estimate of the performance improvement gained by the disk
from the XtremCache acceleration. This is a simulated result and serves a good
reference for how well the application will benefit from XtremCache acceleration.
Figure 18. XtremCache Performance Predictor sample output: disk latency prediction
For best performance, use XtremCache Performance Predictor as a planning tool when
including XtremCache in a VSPEX environment.
VSPEX environments that can benefit from XtremCache
Workload environments with these characteristics can generally benefit from
XtremCache:
44

A high read-to-write workload ratio. The maximum effectiveness is gained
where the same data blocks are read many times and seldom written.

A small working set that receives the maximum possible boost.

Predominantly random workloads. Sequential workloads tend to have a
significantly larger, active dataset in proportion to the available XtremCache
size (such as data warehousing), and so do not benefit greatly from
XtremCache.

A high degree of I/O concurrency (that is, multiple I/O threads).

Smaller I/O sizes (8 KB or lower). Applications that generate a large amount of
I/O, such as Exchange Server 2010, can still benefit.
EMC VSPEX with EMC XtremSF and EMC XtremCache
Design Guide
Chapter 4: Solution Design Considerations and Best Practices
The XtremCache software enables you to tune features such as page size and
maximum I/O sizes, which greatly helps in these environments to continue to
accelerate particular I/O activity and avoid other I/O activity (such as backup read
I/O).
As explained in Chapter 3: Solution Overview, XtremCache can accelerate read
operations, while all write operations are written to the storage array and are not
affected by XtremCache. In many cases, improvement in write-throughput
performance can be observed as XtremCache offloads the read operations, enabling
the array to handle more write operations as a side benefit. XtremCache may not be
suitable for more write-intensive or sequential applications such as data
warehousing, streaming, media, or Big Data applications. Figure 19 shows these use
cases.
Figure 19. XtremCache use cases
The horizontal axis represents a typical read-to-write ratio for an application
workload. The left side represents write-heavy applications such as backups. The
right side represents read-heavy applications such as reporting tools.
The vertical axis represents the working set of the application’s workload. The lower
end represents applications that have a very large working set and the top of the
chart represents applications with a small working set, where the majority of the I/O
goes to a very small set of data. Typically, applications with a small working set
occupy less space in XtremCache.
The greatest performance improvement can be achieved with XtremCache in highread applications with a highly concentrated, small working set of data.
EMC VSPEX with EMC XtremSF and EMC XtremCache
Design Guide
45
Chapter 4: Solution Design Considerations and Best Practices
To summarize, you can use XtremSF as the local storage for read and write
acceleration, temporary data, and large working sets, while XtremSF with XtremCache
can be used for read acceleration of mission-critical data with small working sets that
require data protection.
Selecting an XtremSF card
In general, the two major technologies used in all flash drives are:

SLC NAND-based flash cell

Multilevel cell (MLC) NAND-based flash cell
This section discusses which card to select when designing an XtremCache solution.
EMC XtremSF has both SLC and MLC cards in different sizes to fit the different needs
of a customer environment. For more information about XtremSF card sizes, see Table
3 on page 20.
Design best
practices
Flash storage devices store information in a collection of flash cells made from
floating gate transistors. SLC devices store only one bit of information in each flash
cell (binary). MLC devices store more than one bit per flash cell by choosing between
multiple levels of electrical charge to apply to the floating gates in the transistors, as
shown in Figure 20.
Figure 20. Comparison between SLC and MLC flash cell data storage
MLC versus SLC
Because each cell in MLC flash has more information bits, an MLC flash-based
storage device offers increased storage density compared to an SLC flash-based
version. However, MLC NAND has lower performance and endurance because of its
inherent architectural tradeoffs. Higher functionality further complicates the use of
MLC NAND, which makes it necessary to implement more advanced flash
management algorithms and controllers.
Table 7 compares the SLC and MLC flash characteristics with some typical values.
46
EMC VSPEX with EMC XtremSF and EMC XtremCache
Design Guide
Chapter 4: Solution Design Considerations and Best Practices
Table 7.
SLC and MLC flash comparison
Features
MLC
SLC
Bits per cell
2
1
Endurance (erase/write cycles)
About 10,000
About 100,000
Read service time (Avg.)
129 μs
38 μs
Write service time (Avg.)
1,375 μs
377 μs
Block erase (Avg.)
4,500 μs
1,400 μs
Although SLC NAND Flash offers a lower density, it also provides an enhanced level of
performance in the form of faster reads and writes. Because SLC NAND Flash stores
only one bit per cell, the need for error correction is reduced. SLC also allows for
higher write and erase cycle endurance, making it a better fit for use in applications
that require increased endurance and viability in multiyear product life cycles.
SLC and MLC NAND offer capabilities that serve two different types of applications—
those requiring high performance at an attractive cost per bit (MLC), and those that
are less cost sensitive and seeking even higher performance over time (SLC).
Virtualization design considerations
XtremCache is fully supported when deployed in a virtual environment with VMware
vSphere ESXi technology or Windows Server Hyper-V technology. The following
describes the best practices and design considerations for XtremCache in virtualized
environments:
Sizing
recommendations

Identify the virtual machines on the ESXi server that would be a good candidate
for XtremCache to accelerate its performance with reasonable cost.

Calculate the total capacity needed for XtremCache.

If needed, adjust the placement of the virtual machines in the environment to
best utilize XtremCache.

Select the appropriate XtremSF card for both capacity and performance.
Sizing recommendations are available for each different application type. The
implementation also varies for each different environment. Table 8 shows the
minimum configurations recommended for each application, based on our testing in
a controlled environment with a typical database workload and application workload.
Use the numbers provided as a guideline.
To determine the sizing that best fits a specific application and environment, it is
important to consider both the performance level you need and the cost you can
afford. In most cases, adding more XtremCache gives better performance until the
size of the cache is equal to or greater than the working set.
Table 8 provides XtremCache recommendations for each application. The cache-tostorage ratio (the cache and database storage size ratio, a 1:10 ratio, represents
EMC VSPEX with EMC XtremSF and EMC XtremCache
Design Guide
47
Chapter 4: Solution Design Considerations and Best Practices
a 1 GB XtremCache for each 10 GB of data) largely depends on the active working set
of the database, and will change based on actual usage.
Table 8.
Performance
recommendations
Recommended cache for each application
Application
Database type
Read-to-write
ratio
Recommended
XtremCache-to-storage
ratio2
SQL Server/ Oracle
OLTP
90:10
1:10
SQL Server/ Oracle
OLTP
70:30
1:5
SharePoint Server
Content/crawl
100% read
1:5
Exchange Server
Mailbox
60:40
1:100
For Oracle or SQL Server online analytical processing (OLAP) applications, such as a
data warehouse environment, eMLC XtremSF (alone, or in split-card mode) can be
used as the tempdb to improve the query performance. Consider at least 200 GB
tempdb space for every 1 TB of database.
XtremCache placement considerations
EMC XtremCache can accelerate performance on demand for applications in a VSPEX
Proven Infrastructure.
Flexibility
The flexibility of an XtremCache implementation enables you to place XtremSF on the
server that hosts the specific virtual machines requiring performance acceleration. In
those virtual machines, you enable only the specific storage LUNs that need
XtremCache. To ensure that those virtual machines continue to have access to
XtremCache acceleration, set the appropriate affinity rules for the hypervisor so the
virtual machines can reside only on those servers that are accelerated with XtremSF
Cache.
Additionally, you can install XtremSF Flash cards in all physical servers in the server
infrastructure, and then install and enable XtremCache across all servers.
Design best
practices
Working from the base configuration of VSPEX, for each application you intend to run
within the environment, determine which applications need XtremCache acceleration
by using XtremCache Performance Predictor. This will estimate the benefits of adding
the XtremCache to the environment.
2
XtremCache-to-storage ratio is the cache and database storage size ratio. If the ratio is 1:10,
then for each 10 GB of data, provide at least 1 GB of XtremCache.
48
EMC VSPEX with EMC XtremSF and EMC XtremCache
Design Guide
Chapter 4: Solution Design Considerations and Best Practices
Use XtremCache for read acceleration of mission-critical data with small working sets
that require data protection. Consider the following guidelines when placing the flash
card within the server infrastructure:

Use XtremCache Performance Predictor to estimate the benefits for adding the
XtremCache to the environment

Use XtremCache for read acceleration of mission-critical data with small
working sets that require data protection.

Put at least two XtremSF cards within your VSPEX server infrastructure when
redundancy is required.

If vMotion is required, calculate the XtremSF capacity and placement so that
the remaining server and XtremSF capacity can still serve the configured
XtremCache settings of all virtual machines when vMotion takes place.
For example, you configure 10 virtual machines to use 100 GB of XtremCache,
which requires a total of 1 TB of XtremCache capacity. If vMotion is required,
the remaining servers in the virtualized cluster with XtremCache must facilitate
at least 1 TB of cache space.

If applications only need a small part of the XtremSF card capacity for each
virtual machine, the virtual machines with these applications cab share the
same physical card. You can place them on the same ESXi or Hyper-V host.

If a certain application demands all the available capacity of the XtremSF card,
then the host should dedicate that specific card to the virtual machine. You can
install Multiple XtremSF cards on the same server, if required. You can also
configure multiple XtremSF cards on the same hypervisor or Cache Pool to
create larger cache capacity for virtual machine(s).
The XtremCache page size is the smallest unit of allocation inside the cache. The
default page size is 8 KB. The XtremCache maximum I/O size is the maximum I/O size
that will be promoted into the cache. The default maximum I/O size is 64 KB.
Determine the I/O size distribution of all applications selected for acceleration. If an
application generates significantly large I/O sizes (such as Exchange Server), this
may warrant a change of the default page size and maximum I/O size configurations
for XtremCache.
Figure 21 shows the configuration screen in VSI plugin used to change these
configuration settings. The minimum size for the XtremCache device is 20 GB for any
virtual machine that needs flash cache acceleration.
EMC VSPEX with EMC XtremSF and EMC XtremCache
Design Guide
49
Chapter 4: Solution Design Considerations and Best Practices
Figure 21. Cache device configuration screen
There is minimal resource consumption (overhead) for virtual machines using
XtremCache to accelerate application performance, except when the deduplication
feature is enabled. Resource consumption, including CPU and memory, depends on
the application and especially depends on the size of the working set. Deduplication
introduces very limited memory utilization and CPU consumption when enabled in an
environment with a small working set and high skew. This is detailed in the Exchange
solution example; for more information, see XtremCache for Exchange Server.
XtremCache can be disabled or enabled any time once the XtremSF card is installed
on the physical host and configured for the virtual machine.
VMware considerations
This section provides the most common and important design considerations for
implementing XtremCache in a VSPEX with VMware environment.
The VMware environment in a VSPEX Proven Infrastructure should follow the general
VSPEX design principles and best practices for specific applications on VMware, as
detailed in the VSPEX Implementation Guides.
XtremSF should be installed on each ESXi server with virtual machines that require
XtremCache acceleration, as determined by customer’s performance and cost
analysis.
50
EMC VSPEX with EMC XtremSF and EMC XtremCache
Design Guide
Chapter 4: Solution Design Considerations and Best Practices
After installing the XtremSF Flash card, you can configure the XtremCache pool within
the ESXi cluster using the VSI plug-in or using XtremCache Management Center, as
shown in Figure 22.
Figure 22. XtremCache configuration using EMC VSI plug-in
You can use multiple XtremCache devices in a single cache pool to support larger
cache capacity in certain virtual machines. A single XtremSF cache device can also
support multiple virtual machines’ cache needs, as shown in Figure 23.
Figure 23. XtremCache implementation in VMware environment for VSPEX
EMC VSPEX with EMC XtremSF and EMC XtremCache
Design Guide
51
Chapter 4: Solution Design Considerations and Best Practices
The size of the XtremCache should follow the best practices for each different
application, as previously described in the Sizing recommendations section. For
multiple applications or database LUNs, simply add the required XtremCache device
size, and create a single XtremCache device for the virtual machine, as shown in
Figure 23. The only exception to this is when there is a need to segregate the I/O
traffic, or when one XtremSF card is not big enough for the virtual machine, and then
multiple cache devices are needed.
Since each virtual machine in the VMware environment has its own XtremCache
cache device, there is no contention among different virtual machines for XtremCache
caching. Each deployment should be a careful balance of performance and cost
considerations.
As previously noted, virtual machines are expected to migrate across the VMware
cluster. Ensure that sufficient XtremCache capacity is available on other nodes to
accept an “incoming” virtual machine configured for acceleration. For example, if you
want to move SQLVM1 (configured with a 50 GB cache) from the host ESXServer1 to
the host ESXServer2 (through a vMotion migration), ensure that ESXServer2 has at
least 50 GB of free XtremCache capacity available.
Hyper-V considerations
This section provides the most common and important design considerations for
implementing XtremCache in a Hyper-V environment.
The Hyper-V environment in a VSPEX implementation should follow the general VSPEX
design best practices for the specific application in the Hyper-V environment, as
detailed in the VSPEX Implementation Guides.
As shown in Figure 24, install XtremSF on each Hyper-V server with virtual machines
that require XtremCache acceleration, as determined by the customer’s performance
and cost analysis.
Once the XtremSF card is installed, configure it as the XtremCache target device on
the Hyper-V server. From the Hyper-V server, configure all the LUNs requiring
XtremCache acceleration as source LUNs for the XtremCache target device.
As shown in Figure 24, all VHDXs for the different virtual machines, as well as the
physical pass-through disks on those LUNs configured as XtremCache source LUNs,
are accelerated by XtremCache.
52
EMC VSPEX with EMC XtremSF and EMC XtremCache
Design Guide
Chapter 4: Solution Design Considerations and Best Practices
Figure 24. XtremCache implementation in Hyper-V environment for VSPEX
Since XtremCache in a Hyper-V environment works at the Hyper-V level, all the source
devices from the different virtual machines are accelerated with the same
XtremCache target. This means:

Applications may enjoy a higher level of service from XtremCache when other
virtual machines on the same Hyper-V server are not as active. This is because
the source device is not limited to the calculated capacity of the XtremCache
and can potentially use all the available cache capacity.

There may be contention between different virtual machines if the workload
and active data set (the hot data) on one of the virtual machines is
overwhelmingly high and using more than its quota. To avoid contention, it is
better to put applications that place a high demand on XtremCache on different
Hyper-V servers, or to configure them with a different XtremSF card on the same
Hyper-V server.

Currently, CSV volumes are not supported with XtremCache 1.5x software. CSV
volumes will be supported in future releases.
Note: Volumes in a Hyper-V cluster do not need to be CSV to avail of the benefits of
Live Migration or other advanced Hyper-V features. Also, in cases where Tier-1
applications require acceleration, it may be best not to enable CSV on those volumes
and ensure they are dedicated to the application from the volume to LUN to storage
array disks.

When using VHDX, all VHDXs on the same LUN that are configured with
XtremCache are accelerated with XtremCache. When designing the storage
layout, consider placing only the VHDXs that require XtremCache acceleration
on the LUNs that are configured with XtremCache.
EMC VSPEX with EMC XtremSF and EMC XtremCache
Design Guide
53
Chapter 5: XtremCache Solution for Applications
Chapter 5
XtremCache Solution for
Applications
This chapter presents the following topics:
Overview .............................................................................................................. 55
Architecture of XtremCache deployment on VMware .............................................. 55
Architecture of XtremCache deployment on Hyper-V .............................................. 57
XtremCache for SQL Server OLTP database............................................................ 58
XtremCache for Exchange Server........................................................................... 63
XtremCache for SharePoint ................................................................................... 74
XtremCache for Oracle OLTP database .................................................................. 79
XtremCache for private cloud ................................................................................ 82
54
EMC VSPEX with EMC XtremSF and EMC XtremCache
Design Guide
Chapter 5: XtremCache Solution for Applications
Overview
Any VSPEX Proven Infrastructure that needs to boost the performance of applications
such as Oracle and SQL Server OLTP applications, web applications, financial trading
applications, and Exchange can benefit from XtremCache. XtremCache can be
considered as an upgrade or add-on feature for a larger cloud solution.
This section describes application use cases where XtremCache provides value. It
includes the best practices, the deployment scenarios, and the expected benefits for
the following application use cases:

SQL Server

Exchange

SharePoint

Oracle

Private cloud
Architecture of XtremCache deployment on VMware
Figure 25 shows the validated architecture for an XtremCache deployment on a VSPEX
Private Cloud with VMware. The XtremSF card is installed on the physical VMware
ESXi server and put into an XtremCache pool. The XtremCache device created in that
cache pool is assigned to the virtual machines hosting the application that needs to
be accelerated. The cache device can use part or all of the available storage in the
XtremCache pool.
On each virtual machine, we configured the LUNs that will be accelerated by the
XtremCache as source LUNs for the XtremCache device. After enabling them, data is
cached just as it is in a physical environment. The source LUN can be any LUN in the
virtual machine, such as Virtual Machine Data file for VMware (VMDK) or RDM.
EMC VSPEX with EMC XtremSF and EMC XtremCache
Design Guide
55
Chapter 5: XtremCache Solution for Applications
Figure 25. Architecture of the VSPEX Proven Infrastructure for XtremCache deployment on
VMware
56
EMC VSPEX with EMC XtremSF and EMC XtremCache
Design Guide
Chapter 5: XtremCache Solution for Applications
Architecture of XtremCache deployment on Hyper-V
Figure 26 shows the validated architecture for an XtremCache deployment on a VSPEX
Private Cloud with Hyper-V. In a Hyper-V environment, the XtremCache is deployed on
the Hyper-V host and managed from this level. The I/O issued by the virtual machines
is accelerated at the Hyper-V level. If there are multiple VHDXs on the same LUN in the
Hyper-V host, they will all be accelerated because the XtremCache source LUN is
configured at the Hyper-V host level.
If a VHDX is used in Hyper-V, the source LUN for XtremCache on the Hyper-V host
should contain only VHDXs that need to be accelerated.
Figure 26. Architecture of the VSPEX Proven Infrastructure for XtremCache deployment on
Hyper-V
EMC VSPEX with EMC XtremSF and EMC XtremCache
Design Guide
57
Chapter 5: XtremCache Solution for Applications
XtremCache for SQL Server OLTP database
In a SQL Server environment, the storage LUNs that host the database data files for
the OLTP database are most likely to benefit from XtremCache acceleration.
The read-to-write ratio of a typical SQL Server OLTP database data file ranges from
70:30 to 90:10, making the database data file LUN ideal for XtremCache acceleration.
In the example use case described in this section, we tested an active OLTP database
with a read-to-write ratio of 90:10. Using about a 100 GB cache to accelerate a 1 TB
OLTP database reduced the read latency by more than half.
Benefits of
XtremCache in a
SQL Server OLTP
environment
XtremCache is proven to be highly scalable and reliable. It can relieve the I/O
processing pressure from the storage system and boost the disk read operations
driven by the host, even in virtual ESXi-based environments. XtremCache increases
the overall transaction rate of SQL Server and significantly reduces disk latencies with
minimal impact on system resources.
XtremCache in SQL Server OLTP environments provides the following benefits:
58

XtremCache can reduce SQL Server storage response time.

The XtremCache host driver has minimal impact on server and virtual machine
system resources. In testing, the system resources were mostly consumed by
the SQL Server workload. The XtremCache driver overhead was negligible—0.4
percent CPU usage in this example use case.

With a highly optimized, multitier storage system, XtremCache can offload read
I/O processing from the storage array while reducing disk latencies, thus
enabling higher transactional throughput and enabling the EMC storage array to
consume even more workload.

With less optimized, two-tier storage configurations, XtremCache can
significantly boost SQL Server transactions and lower overall host disk latency.
It can address “hot-spots” in the datacenter and alleviate possible storage
bottlenecks.

We observed a performance boost immediately after the LUNs were added to
the XtremCache pool. Performance reached a steady state in approximately one
hour for all 16 LUNs hosting a 3 TB database file.

XtremCache is a server-based cache. Introducing XtremCache to a storage
environment does not require any changes to the application or storage system
layouts.

Because XtremCache is a caching solution rather than a storage solution, there
is no need to move data. Therefore, you do not risk having inaccessible data if
the server or the PCIe card fails.

XtremCache minimizes CPU overhead in the server by offloading flash
management operations from the host CPU onto the PCIe card.

Managing and monitoring XtremCache in a vSphere environment is easy. After
configuration, XtremCache requires no user intervention and continuously
adjusts to meet the needs of the application workload.
EMC VSPEX with EMC XtremSF and EMC XtremCache
Design Guide
Chapter 5: XtremCache Solution for Applications
Best practices
Based on the XtremCache Performance Predictor, in a SQL Server OLTP environment
running a heavy OLTP workload, the primary database LUNs can benefit most from
XtremCache acceleration. The log LUNs and tempdb LUNs are write-heavy and should
not be used with the XtremCache.
In summary, in a typical SQL Server OLTP environment:
Use case design
and deployment

You should use XtremCache Performance Predictor to estimate the benefits for
adding the XtremCache to SQL server environment.

The read-intensive database data file LUNs generally have heavy workload,
subjected to a high-read skew, and are good candidates for XtremCache.

SQL Server OLTP data files experience constant random reads and contribute to
the overall duration of transaction times. Data files also experience regular
bursts of write activity during a checkpoint operation. Using XtremCache to
perform cache reads and avoid an I/O workload on the EMC array enables the
array to consume those burst writes faster and avoid any read delays for
transactions.

Log LUNs and tempdb LUNs in OLTP databases are write-intensive and typically
do not benefit from XtremCache.

In SQL Server AlwaysOn environments, the secondary databases do not need to
be accelerated unless a specific performance requirement justifies the use of
XtremCache.

Set the page size to 64 KB in the XtremCache to accommodate the large I/O for
the SQL Server database.

If the workload is not expected to increase after deploying XtremCache in the
VSPEX Proven Infrastructure, there is no need for additional system resources
such as memory or CPU.

With a read-to-write ratio of 90:10 in the OLTP database LUNs, for each 1 TB of
database, an XtremCache of 100 GB or more would significantly improve the
OLTP query performance and read operations.
The example use case deployed XtremCache to accelerate OLTP performance in a
multiuser SQL Server 2012 database virtualized with the VMware environment. Two
ESXi servers each hosted one SQL Server virtual machine. One of the SQL Server
virtual machines used a 700 GB SLC XtremSF card. The other server did not have
XtremCache configured.
The environment is based on a multitier storage solution that is controlled and
optimized by EMC Fully Automated Storage Tiering for Virtual Pools (FAST VP).
The solution design includes the following components and features as shown in
Figure 27:

Two vSphere ESXi servers, each hosting one SQL Server virtual machine

XtremCache enabled on the primary SQL Server virtual machine
EMC VSPEX with EMC XtremSF and EMC XtremCache
Design Guide
59
Chapter 5: XtremCache Solution for Applications
Figure 27. Architecture design for XtremCache enabled SQL Server virtual environment
Deployment scenarios
Figure 28 shows the XtremCache deployment for this use case. All the database file
LUNs on the primary server are configured as source LUNs for XtremCache
acceleration; tempdb LUNs and log LUNs are excluded. The secondary server does
not have XtremCache configured.
60
EMC VSPEX with EMC XtremSF and EMC XtremCache
Design Guide
Chapter 5: XtremCache Solution for Applications
Figure 28. SQL Server AlwaysOn XtremCache deployment
Configuration of
XtremCache in the
VMware
environment
In this solution, we configured one 278 GB XtremCache. All 16 source data devices
were associated with the cache device, as shown in Figure 28.
Configuration is straightforward using the wizards in the VSI integrated plug-in. If
preferred, you can use the command line from the Windows virtual machine.
Perform the following steps to configure the XtremCache for the database LUNs in the
virtual machine:
1.
Use vCenter Server to create a VMFS datastore, and then create XtremCache
pool with the XtremSF card in the ESXi server.
2.
Create the XtremCache device from the Cache pool and assign it to the virtual
machines through the VSI plug-in for XtremCache.
3.
Add the source devices to the enabled XtremCache device to accelerate their
performance.
Any source device can be stopped temporarily or removed from the caching operation
without affecting other source devices.
Test results
XtremCache boosts system performance
After enabling XtremCache for the first time, the performance boost was visible
immediately.
XtremCache started to take effect as soon as it was enabled with the devices needing
a performance boost added into the cache pool. It took approximately one hour in
this environment to reach the maximum performance boost.
We tested XtremCache for SQL Server in both a two-tier and three-tier configuration.
Figure 29 shows the read and write IOPS for the primary SQL Server before and after
enabling XtremCache in a two-tier storage system.
EMC VSPEX with EMC XtremSF and EMC XtremCache
Design Guide
61
Chapter 5: XtremCache Solution for Applications
IOPS and latency change after enabling XtremCache
Baseline | XtremCache Enabled
20,000
12
8
6
10,000
4
5,000
latency (ms)
10
15,000
IOPS
Steady state
2
0
0
IOPS
latency ( ms)
Figure 29. Performance boost after enabling XtremCache
After the system reached the steady state, the system performance was stable
during the 24-hour testing period.
XtremCache reduces SQL Server response time
XtremCache significantly reduced the SQL Server response time for high response
time transactions in both the two-tier and three-tier configurations.
The XtremCache host driver had a minimal impact on the server and virtual machine
system resources. The read latency reduced by approximately 50 to 70 percent after
we enabled XtremCache. We observed a similar result with the transaction latency,
where XtremCache also significantly lowered the response time of high latency
transactions.
Without XtremCache, the two-tier configuration can support only 14,000 IOPS. With
XtremCache, it can fully support a 24,000 IOPS load with a 90:10 read-to-write ratio.
XtremCache significantly lowered the I/O activities on the storage array (about
10,000 IOPS) in the three-tier configuration, thus enabling the storage system to
support more server I/O requests.
62
EMC VSPEX with EMC XtremSF and EMC XtremCache
Design Guide
Chapter 5: XtremCache Solution for Applications
Table 9 shows the detailed test results for all the test scenarios in this
solution.
Table 9.
Performance data with OLTP load
Three-tier storage
Two-tier storage
Without
XtremCache
With
XtremCache
Without
XtremCache
With
XtremCache
SQL Server virtual machine CPU
67.45%
67.85%
15.50%*
51.43%
ESXi CPU
77.80%
78.20%
24.63%*
65.57%
Client transactions per second
(TPS)
2,193
2,585
1,225
2,229
SQL Server virtual machine IOPS
23,938
23,916
14,123
23,602
Array front-end IOPS
24,698
14,987
15,475
13,798
Latency (ms) (read/write/transfer)
4/1/4
2/2/2
11/1/10
4/3/4
Performance
* CPU usage was lower because the storage bottleneck created in this test limited the client load that
can be pushed to the system.
XtremCache for Exchange Server
In an Exchange Server environment, the Exchange database LUNs are most likely to
benefit from XtremCache acceleration.
The performance of the database can be improved by using 10 GB of XtremCache for
each 1 TB of Exchange data in the Mailbox server virtual machines in the example use
case described in this section.
Even though the typical Exchange Mailbox workload has about a 60:40 read-to-write
ratio and a large I/O size, the working set of the Exchange databases is very small.
This means that the Mailbox workload performance can be dramatically improved
when a small slice of XtremSF is configured as XtremCache for the Mailbox database
LUNs. The high I/O skew in this use case also makes it a good candidate for
deduplication with limited memory and CPU consumption.
Benefits of
XtremCache in an
Exchange
environment
Using XtremCache in an Exchange environment offers many benefits:

XtremCache improves Exchange performance by reducing read latencies and
offloading read operations from the back-end storage.

XtremCache helps to maximize I/O throughput for Exchange workloads without
changing or adding any additional storage resources.

XtremCache reduces bandwidth requirements through deduplication features,
offloading write processing from the Exchange back-end storage.
EMC VSPEX with EMC XtremSF and EMC XtremCache
Design Guide
63
Chapter 5: XtremCache Solution for Applications
Best practices

XtremCache can be integrated with vSphere for virtual machine migration that
has an XtremCache device attached. With proper configuration, the
applications can resume the accelerated state after virtual machine automigration occurred.

XtremCache has little impact on system resources such as CPU and memory.

The initial warm-up period for XtremCache with Exchange-simulated workloads
varies for each environment. In this solution, the effect of XtremCache was
observed immediately after it was enabled. It reached a steady state in
approximately 30 minutes for all Exchange accelerated database LUNs with 15
TB of data.

Integration with the VSI plug-in for VMware makes XtremCache easy to manage
and monitor in a virtualized environment.

XtremCache is designed to minimize CPU overhead in the server by offloading
flash management operations from the host CPU onto the XtremSF PCIe card.

With an Exchange workload, XtremCache can relieve I/O processing pressure
from the storage system and boost the disk read operations driven by the host.

XtremCache increases the overall Exchange application IOPS and significantly
reduces disk latencies with minimal impact on system resources.

Using XtremCache enables customers to configure Exchange for high
performance and low cost without making trade-offs.

Managing and monitoring XtremCache in a vSphere environment is easy. After
configuration, XtremCache requires no user intervention and continuously
changes to meet the application workload requirements.
In an Exchange environment configured with Database Availability Groups (DAGs) (for
both active and passive copies of DAG), and based on the XtremCache performance
predictor tool results, the LUNs for the databases can benefit most from XtremCache
acceleration.
More importantly, the working set for Exchange database is relatively small; thus, the
XtremCache size needed for Exchange server acceleration is also small. In this use
case, every 1 TB of Exchange data requires only about 10 GB of XtremCache. Enabling
XtremCache acceleration for both active and passive databases also improves the
performance. If there is a DAG failover, XtremCache is already warm when the DAG
fails over and the whole Exchange environment shows almost no performance
impact. The LUNs for the database log should be excluded because of their
sequential workload.
In summary, in a typical Exchange environment:
64

Use XtremCache Performance Predictor to estimate the benefits of adding
XtremCache to the Exchange environment.

In Mailbox virtual machines, typically both active and passive database file
LUNs with a heavy workload are good candidates for XtremCache source LUNs.
XtremCache also helps improve the performance even in a DAG failover
scenario.
EMC VSPEX with EMC XtremSF and EMC XtremCache
Design Guide
Chapter 5: XtremCache Solution for Applications
Use case design
and deployment

You should typically exclude log LUNs from XtremCache.

Set the page size to 64 KB in XtremCache to accommodate the large I/O size of
the Exchange Server.

For each Exchange virtual machine, for every 1 TB of Exchange data, configure
about a 10 GB XtremCache to significantly improve the Mailbox server
performance.
The example use case deployed XtremCache to accelerate the performance of
Exchange 2010 in a DAG configuration with two database copies virtualized with the
VMware environment.
We installed two 700 GB SLC XtremSF cards on the vSphere ESXi servers hosting six
Exchange Mailbox server virtual machines.
In testing, the system IOPS improved by over 26 percent, and read latencies
decreased by about 50 to 70 percent.
We also tested the environment for deduplication with little additional system
resource consumption. When enabling XtremCache deduplication for Exchange
Server, you can reduce the CPU usage by up to 50 percent in certain workloads, with a
drop of up to 30 percent in the write IOPS to the back-end array.
Figure 30 shows the solution design, which included the following components:

A vSphere HA cluster consisting of two vSphere ESXi servers, each hosting
three Exchange Mailbox server virtual machines

Two copies of the DAG database configured on different Mailbox servers

XtremSF installed on both ESXi servers in the HA cluster

Each Exchange Mailbox server virtual machine configured with a 50 GB
XtremCache for their 5 TB databases (including both active and passive DAG
copies).
EMC VSPEX with EMC XtremSF and EMC XtremCache
Design Guide
65
Chapter 5: XtremCache Solution for Applications
Figure 30. Architecture design for XtremCache-enabled Exchange virtual environment
Deployment scenarios
Figure 31 shows the XtremCache deployment for the Exchange use case. We
configured all database LUNs for active and passive copies on the virtual machines
as source LUNs for XtremCache acceleration. The log LUNs were excluded mostly
because of their write and sequential I/O.
66
EMC VSPEX with EMC XtremSF and EMC XtremCache
Design Guide
Chapter 5: XtremCache Solution for Applications
Figure 31. XtremCache deployment for Exchange 2010 on vSphere
In this deployment, for each virtual machine with 5 TB of storage, we deployed 50 GB
of XtremCache. We configured the rest of the XtremCache capacity to support the
vMotion failover.
Configuration of
XtremCache in the
VMware
environment
The configuration of XtremCache for an Exchange Mailbox server in a VMware
environment is similar to the SQL Server configuration previously shown in Figure 28.
In addition, for this use case, we configured deduplication and vMotion migration.
You can configure the XtremCache data deduplication feature for the Exchange
Mailbox server virtual machines. Data deduplication eliminates redundant data by
storing only a single copy of identical chunks of data while, at the same time,
providing access to the data from the cache. Deduplication also helps to reduce
storage and bandwidth requirements and extend the life expectancy of the cache
device.
Configuring the XtremCache device with data deduplication
To enable data deduplication for the XtremCache device, follow these steps:
1.
Select the Use Data Deduplication checkbox in the Add XtremCache Device
wizard, when adding the XtremCache device to a virtual machine.
EMC VSPEX with EMC XtremSF and EMC XtremCache
Design Guide
67
Chapter 5: XtremCache Solution for Applications
2.
Select the expected data deduplication gain based on your Exchange
workload type, as shown in Figure 32.
Figure 32. Enabling data deduplication on the XtremCache device
You can also enable data deduplication using the XtremCache CLI on the Windows
client machine by running the following command:
vfcmt add -cache_dev harddisk13 –set_page_size 64 –set_max_io_size
64 –enable_ddup –ddup_gain 20
Where:
Is:
harddisk13
A configured operating-system cache device for the virtual machine
ddup_gain 20
The deduplication gain percentage for the system cache device on the
virtual machine
After adding the deduplication-enabled XtremCache device, add the Exchange
database LUNs as source devices to the XtremCache device for performance
acceleration.
To determine the appropriate data deduplication gain for your Exchange workload,
review the XtremCache statistics information in the XtremCache VSI plug-in or use the
CLI on the Windows server. After the cache warm-up, follow these recommendations:
68

Calculate the observed deduplication hit ratio and compare it with the
configured ratio.

Calculate the observed deduplication hit ratio by dividing the Write Hits by the
Writes Received. This is the amount of duplicated data in the cache.

If the observed ratio is less than 10 percent, turn off deduplication or
reconfigure the deduplication gain to zero percent. To benefit from the
extended life of the cache device, keep deduplication enabled.
EMC VSPEX with EMC XtremSF and EMC XtremCache
Design Guide
Chapter 5: XtremCache Solution for Applications

If the observed ratio is over 35 percent, raise the deduplication gain to match
the observed deduplication.

If the observed ratio is between 10 and 35 percent, leave the deduplication
gain as it is.
To change the configured ratio, remove the XtremCache device from the Exchange
Mailbox server virtual machine, and add it back again with a new deduplication
percentage value. To do this, use the VSI plug-in or the CLI command (vfcmt add cache_dev), as described previously in this section.
Migrating an Exchange virtual machine with XtremCache device
It is possible to move an Exchange virtual machine that has an XtremCache disk from
one vSphere host to another. Under a typical scenario, without an XtremCache
device, you can use the native vSphere migrate command to move a virtual machine
from one host to another. This is possible because in a typical scenario the virtual
machine’s datastores and RDMs are shared resources.
In the XtremCache environment, however, the XtremCache datastore is mapped to its
local host flash drive. Consequently, this datastore is accessible only to that host and
the native vSphere migrate command is not supported. Instead, use the EMC
XtremCache VSI plug-in to perform the virtual machine migration with the XtremCache
device attached.
Multiple forms of migration are available. The form of migration that you choose
determines the steps you perform to complete the migration.
Before you begin, ensure that your system meets the following prerequisites:

The target datastore has enough available capacity for the new device.

There are no additional DAS flash-based devices for the host virtual machine.

Only one XtremCache device is configured on the host virtual machine.

The virtual machine you want to migrate is not currently being migrated.
The source host and the target host must be able to communicate with each other, so
ensure the IP and Domain Name System (DNS) have been properly configured.
Recovering Exchange data from a snapshot
If you are using backup software that performs snapshots of Exchange LUNs
accelerated by XtremCache, follow specific procedures when restoring data from
those snapshots to ensure data integrity.
If an Exchange LUN snapshot is taken on the array, and later used to roll back
changes on the source LUN, the server will not be updated with the changes. This
could result in the cache supplying data that may not been updated with the contents
of the snapshot.
To prevent this from occurring, when recovering from the snapshot, perform the
following steps:
1.
Quiesce the application that is accessing the source volume using
application-specific tools, such as EMC Replication Manager.
EMC VSPEX with EMC XtremSF and EMC XtremCache
Design Guide
69
Chapter 5: XtremCache Solution for Applications
Test results
2.
Flush the data in the host buffers using an appropriate command, such as
admsnap flush, and unmount the file system.
3.
Invalidate the contents of the source device by using the purge source_dev command.
4.
Perform the snapshot restore operations on the array.
5.
After the restore is complete, remount the file system, as necessary.
XtremCache acceleration test results
We observed consistent reductions in read latencies and increased user IOPS with all
workload types when we enabled XtremCache to accelerate performance for the
database LUNs. Even 300-message workloads that experienced over 20 ms read
latencies without XtremCache became a normal steady workload with reduced
latencies and increased IOPS with XtremCache enabled. This extreme workload was
expected to fail as the storage and Exchange virtual machine resources were
originally designed for 150-message workloads.
Figure 33 provides additional details for each test performed. Highlights of the
observed test results include:
70

A 150-message per user per day workload achieved a 51 percent reduction in
read latencies (by 6.4 ms) and a 14.6 percent increase in user IOPS (by 224
IOPS).

A 250-message per user per day workload achieved a 69.3 percent reduction in
read latencies (by 11.1 ms) and a 12.8 percent increase in user IOPS (by 275
IOPS).

A 300-message per user per day workload achieved a 56.8 percent reduction in
read latencies (by 12.5 ms) and a 12 percent increase in user IOPS (by 346
IOPS).
EMC VSPEX with EMC XtremSF and EMC XtremCache
Design Guide
Chapter 5: XtremCache Solution for Applications
Figure 33. Exchange 2010 performance with XtremCache and LoadGen workload
Performance with XtremCache data deduplication
To validate Exchange performance with XtremCache inline data deduplication, we
performed validation on one Exchange virtual machine with 5,000 users. We
performed a series of Microsoft Exchange Load Generator (LoadGen) tests, with each
test lasting eight hours and with multiple workload profiles, to see the effect of data
deduplication. We monitored the XtremCache statistics to determine the appropriate
deduplication ratio for each workload. With the LoadGen workloads we generated, we
observed that a 30 percent deduplication ratio would be more effective than the
default 20 percent. Figure 34 shows the deduplication ratio observed during testing.
Figure 34. XtremCache statistics with data deduplication
Note: The LoadGen workload does not represent the actual workload in your specific
production environment. The results observed and recommendations provided here are
based on our lab configuration and results only. Ensure that you configure your environment
based on your particular workload requirements and characteristics.
EMC VSPEX with EMC XtremSF and EMC XtremCache
Design Guide
71
Chapter 5: XtremCache Solution for Applications
Deduplication test results summary
In Figure 35 and Figure 36, the XtremCache data deduplication test results with
multiple workload profiles for the Exchange 2010 Mailbox server show:
72

Decreased Exchange Server CPU utilization with each workload

Slightly increased write latencies due to XtremCache analysis and processing of
the duplicated data
EMC VSPEX with EMC XtremSF and EMC XtremCache
Design Guide
Chapter 5: XtremCache Solution for Applications
Figure 35. Exchange server CPU utilization with XtremCache data deduplication
Figure 36. Exchange server disk latencies with XtremCache data deduplication
EMC VSPEX with EMC XtremSF and EMC XtremCache
Design Guide
73
Chapter 5: XtremCache Solution for Applications
Analysis of the back-end VNX storage array shows that when we enabled
deduplication on the server, the writes to the VNX array were reduced. In Figure 37,
the write activity was reduced from 90 IOPS to around 65 IOPS for one of the
database LUNs, which is about a 27.7 percent difference.
Figure 37. Exchange database LUN performance with XtremCache data deduplication
XtremCache for SharePoint
For the SharePoint environment, content database and crawl database LUNs are most
suitable for XtremCache acceleration.
A typical SharePoint content database workload has a 70:30 read-to-write ratio,
making it an ideal candidate for XtremCache acceleration. With two 600 GB
XtremCache devices configured on two 700 GB XtremSF cards, the database latency
can drop to less than one third during a full crawl.
Benefits of
XtremCache in a
SharePoint
environment
Best practices
This use case demonstrates the following results:

XtremCache offloads the read workload of the SharePoint content database
workload during the crawl process from the storage array to the server.

XtremCache improves the crawl performance by lowering the latencies in the
content database of the SharePoint farm in a virtualized environment.

XtremCache has little impact on system resources such as CPU and memory.

Integration with the VSI plug-in for VMware vSphere vCenter makes XtremCache
easy to manage and monitor in a virtualized environment.
In a SharePoint environment, based on the XtremCache Performance Predictor tool,
the LUNs for the content databases during the crawl process can benefit most from
XtremCache acceleration. The database file LUNs for the content database are,
therefore, good candidates for the XtremCache source LUNs. Exclude the log LUNs
and tempdb LUNs from XtremCache as they are mostly write-heavy.
In summary, in a typical SharePoint Farm:

74
Use XtremCache Performance Predictor to estimate the benefits of adding
XtremCache to SharePoint Farm.
EMC VSPEX with EMC XtremSF and EMC XtremCache
Design Guide
Chapter 5: XtremCache Solution for Applications
Use case design
and deployment

The content database files LUNs and crawl database LUNs with a heavy
workload are good candidates for the XtremCache source LUNs.

Log LUNs and tempdb LUNs in the SharePoint farm are excluded from the
acceleration of XtremCache.

Set the page size to 64 KB and the maximum I/O size to 128 KB in the
XtremCache to accommodate the large I/O size of the content and crawl
databases, especially when NFS is in use.

For each 1 TB of the content database, an XtremCache of 200 GB or more can
significantly improve the OLTP query performance.
The example use case deployed a virtualized SharePoint 2010 farm with 1.8 TB
content databases in one SQL Server 2012 virtual machine in a vSphere 5.1
virtualized environment, configured with two 700 GB XtremSF cards. You can improve
the performance of the SharePoint crawl by:

Deploying 600 GB XtremCache in the SQL Server virtual machine

Configuring all the content database file LUNs and the crawl database file LUNs
to be accelerated by the XtremCache
The latency for these LUNs decreases dramatically and the crawl performance
improves by more than 20 percent.
The configuration of XtremCache for SharePoint in a VMware environment is similar to
the SQL Server configuration. Only the SQL Server virtual machine in the SharePoint
farm needs XtremCache acceleration.
The solution design includes the following components, as shown in Figure 38:

XtremSF installed on vSphere ESXi servers hosting the SQL Server virtual
machine for SharePoint Server

XtremCache enabled on the SQL Server virtual machine, only configured for the
content databases and the crawl databases

Storage tiers with FAST VP enabled
EMC VSPEX with EMC XtremSF and EMC XtremCache
Design Guide
75
Chapter 5: XtremCache Solution for Applications
Figure 38. Architecture design for XtremCache enabled SharePoint environment
Deployment scenarios
Figure 39 shows the XtremCache deployment for this use case. All the content
database file LUNs are configured as source LUNs for XtremCache acceleration, but
tempdb LUNs and log LUNs are excluded.
76
EMC VSPEX with EMC XtremSF and EMC XtremCache
Design Guide
Chapter 5: XtremCache Solution for Applications
Figure 39. XtremCache deployment for SharePoint 2010 on vSphere
Configuration of
XtremCache in the
VMware
environment
In this solution, two cache devices with a usable size of 600 GB out of the 700 GB
XtremCache card are configured for the content database virtual machine. All the
LUNs for the content databases data file and the crawl database data file are
associated with the two cache devices.
During the crawl process, the content database data file is 100 percent random read
and the crawl database data file is around 60 percent read. Set the I/O page size for
the cache device to 64 KB (the default is 8 KB) and the maximum I/O size to 128 KB
(the default is 64 KB).
Test results
The Read Hit rate for the content database during a full crawl is about 70 to 75
percent, and the crawl database is around 40 percent.
The hard disks that store the content databases all have an over 70 percent Read Hit
rate. The Read Hit rate is around 40 percent for the crawl database hard disk.
The latency of the content databases and crawl database dropped dramatically after
we enabled the cache device, as shown in Figure 40. Note that the property database
is not configured as source devices for cache. The latency drop contributed to the
property database improvement because it was in the same disk pool in the storage
array. As the I/O on the backend for the content and crawl database were offloaded to
EMC VSPEX with EMC XtremSF and EMC XtremCache
Design Guide
77
Chapter 5: XtremCache Solution for Applications
the XtremCache, a side effect was an improvement in the latency for the property
database.
Figure 40. Content database latency dropped after enabling XtremCache
The full crawl duration decreased by 21.2 percent when XtremCache was enabled, as
shown in Figure 41
.
Figure 41. Full crawl performance improved after enabling XtremCache
78
EMC VSPEX with EMC XtremSF and EMC XtremCache
Design Guide
Chapter 5: XtremCache Solution for Applications
XtremCache for Oracle OLTP database
In the VSPEX for virtualized Oracle environment, the database LUN for the OLTP
database is most likely to benefit from XtremCache acceleration.
We tested a database with a read-to-write ratio of 70:30. Within an XtremCache of
200 GB to accelerate 1 TB of the database LUN, the transaction rate almost doubled.
Benefits of
XtremCache in an
Oracle
environment
Best practices
Similar to the application environments described previously, the VSPEX for
virtualized Oracle environment will benefit from XtremCache as a server-based cache.
Introducing the XtremCache virtual infrastructure does not require any changes to the
application or storage system layouts. Because XtremCache is a caching solution
rather than a storage solution, there is no need to move data. Therefore, your data is
not at risk of becoming inaccessible if the server or the PCIe card fails. XtremCache is
designed to minimize CPU overhead in the server by offloading flash management
operations from the host CPU to the PCIe card. In a virtualized Oracle OLTP
environment, XtremCache:

Delivers an 80 percent improvement in transactions per minute (TPM)
compared to the baseline without any changes to applications

Maintains the integrity of and protects the data
In an Oracle Database 11g R2 environment, based on the XtremCache Performance
Predictor tool, the database file LUNs can benefit most from XtremCache acceleration
and are good candidates for the XtremCache source LUNs.
In summary, in a typical Oracle OLTP environment:
Use case design
and deployment

Use the XtremCache Performance Predictor tool to estimate the benefits of
adding XtremCache to the environment.

The database file LUNs with a heavy workload are good candidates for the
XtremCache source LUNs.

Log LUNs and tempdb LUNs in the OLTP databases are excluded from the
acceleration of XtremCache.

For each 1 TB of database with a read-to-write ratio of 70:30, an XtremCache of
200 GB or more can significantly improve the performance of the database.
The example use case deployed a standard TPC-C-like OLTP workload, with a 1.2 TB
database and a 70 to 30 percent read/write mix on Oracle Database 11g R2 on a Red
Hat Enterprise Linux 5 virtual machine virtualized with vSphere 5.1. By deploying 250
GB of usable XtremCache in the Oracle virtual machine from a single 350 GB XtremSF
card, the performance of the workload can be dramatically improved. The
transactions per minute improved 80 percent compared with the same environment
without XtremCache.
EMC VSPEX with EMC XtremSF and EMC XtremCache
Design Guide
79
Chapter 5: XtremCache Solution for Applications
The solution design includes the physical components shown in Figure 42:

A single vSphere ESXi server hosting one Oracle Database 11g R2 server on a
Red Hat Enterprise Linux 5 virtual machine

A 1.2 TB database on eight VMDK LUNs for the database files and two VMDK
LUNs for the logs

XtremSF installed on the ESXi server with a 250 GB XtremCache configured for
the Oracle virtual machine
We configured only database VMDKs as source LUNs for XtremCache. We excluded
the log LUNs and the tempdb LUNs.
Figure 42. Architecture design for XtremCache enabled Oracle 11g R2 environment
80
EMC VSPEX with EMC XtremSF and EMC XtremCache
Design Guide
Chapter 5: XtremCache Solution for Applications
Deployment scenarios
Figure 43 shows the XtremCache deployment for the Oracle use case. We configured
all of the database VMDK LUNs on the virtual machines as source LUNs for
XtremCache acceleration. We excluded log LUNs because of their write-intensive
nature. In this deployment, we configured 250 GB of XtremCache for caching 1.2 TB of
the OLTP database.
Figure 43. XtremCache deployment for Oracle 11g R2 on vSphere
Configuring XtremCache for Oracle in a VMware environment is similar to configuring
the other application environments described in the previous sections.
Test results
Figure 44 compares the overall system throughput (in TPM) of the baseline and
XtremCache-enabled environments. The availability of the hot data in the server’s
XtremCache resulted in an 80 percent improvement in transactions per minute.
EMC VSPEX with EMC XtremSF and EMC XtremCache
Design Guide
81
Chapter 5: XtremCache Solution for Applications
Figure 44. OLTP TPM improvement
XtremCache for private cloud
This use case deployed the XtremCache to accelerate performance of the following
applications in a private cloud environment virtualized with VMware:

Oracle Database 11g R2 OLTP database

SQL Server OLTP database

SQL Server decision support system (DSS) database

SQL Server 2012 cluster
In the Oracle and SQL Server OLTP virtual machines, we configured the XtremCache
based on the principals described in the previous application-specific sections. The
cluster support configured XtremCache for both active and passive databases. SQL
Server DSS uses XtremSF storage in a split configuration for the tempdb of the DSS
database.
With a comprehensive private cloud environment, XtremCache and XtremSF proved to
be flexible and were able to deliver the expected performance improvement for all the
applications in different configurations.
XtremCache is proven to complement FAST VP for performance improvement of both
the SQL Server and Oracle OLTP databases.
The tempdb, supported by XtremSF in the database for the DSS workload, gets a
performance boost from the XtremSF.
82
EMC VSPEX with EMC XtremSF and EMC XtremCache
Design Guide
Chapter 5: XtremCache Solution for Applications
Benefits of
XtremCache in a
private cloud
environment
This EMC solution has shown the implementation of multiple critical applications in a
VMware private cloud environment, supported by XtremSF and XtremCache. Each
application had different workload characteristics and placed varying demands on
the underlying storage. XtremCache provided better performance for the applications
that involve heavy read I/O.
The benefits of XtremCache in a private cloud environment include the following:

Performance optimization—accelerating application-specific performance at
the host level using EMC XtremSF cards:

With a three-tier FAST VP configuration, XtremCache offloads the IOPS of
the array significantly. The array can be free for other I/O requests.

With a two-tier FAST VP configuration, XtremCache reduces disk latencies
and response times, enabling a higher transaction throughput.

XtremCache reduces disk latencies and response time, enabling higher
transaction throughput by offloading much of the read I/O traffic from the
storage array.

XtremCache caches the read I/O so the data is not at risk of being inaccessible
if the server or the XtremCache card fails.

Using XtremSF storage in a split-card configuration for the tempdb of the DSS
database boosts the performance of the tempdb.

XtremCache in a virtualized environment is easy to manage and monitor due to
its integration with the VSI plug-in to VMware vSphere vCenter.

XtremCache deduplication helps to reduce the footprint on bandwidth.
In this private cloud environment, XtremCache demonstrated both flexibility and ease
of management in a comprehensive configuration, improving performance while
having little impact on system resource consumption.
Best practices
In a private cloud environment, you need to consider multiple applications. Follow
the application-specific best practices, particularly for the deployment of XtremCache
in a heterogeneous environment:

Always use the XtremCache Performance Predictor tool to determine which
application can benefit from XtremCache the most.

Allocate XtremCache for the most critical application virtual machine first, and
then consider the rest of the virtual machines.

Consider placing virtual machines on a different physical server to optimize the
capacity of XtremSF.

MLC XtremSF (alone or in split-card mode) can be used as a tempdb for data
warehouse or DSS types of databases. To improve query performance, consider
allowing at least 200 GB of tempdb space for every 1 TB of database.
EMC VSPEX with EMC XtremSF and EMC XtremCache
Design Guide
83
Chapter 5: XtremCache Solution for Applications
Use case design
and deployment
In the example use case, Microsoft SQL Server 2012 (two OLTP and one DSS), Oracle
Database 11g R2 (OLTP), and Microsoft SQL Server failover clustering are all on the
virtualized environment. These applications ran on virtual machines in a VMware
vSphere 5 environments on FAST VP-enabled EMC storage, which continually
monitors and tunes performance by relocating data across tiers based on access
patterns and predefined FAST policies.
We deployed XtremSF on both ESXi servers, one configured in a split-card mode. We
configured XtremCache to support the OLTP databases for caching purposes, while
using the remaining XtremSF capacity for the storage of tempdb in the DSS database.
Load generation tools drove these applications simultaneously to validate the
infrastructure and function of XtremCache acceleration to the data LUNs of the OLTP
application.
The solution design included the following components, as shown in Figure 45:
84

Two vSphere ESXi servers, one hosting the Oracle Database 11g R2 server and
a SQL Server virtual machine as part of Microsoft Server failover cluster; the
other hosting the other SQL Server of the MSCS, two SQL Servers with OLTP,
and one SQL Server with a DSS workload.

XtremSF configured in split-mode is used as tempdb storage for the SQL Server
virtual machine with the DSS workload.

XtremCache enabled on all other virtual machines.

FAST VP-enabled storage tiers.
EMC VSPEX with EMC XtremSF and EMC XtremCache
Design Guide
Chapter 5: XtremCache Solution for Applications
Figure 45. Architecture design for XtremCache-enabled private cloud environment with
multiple applications
Deployment scenarios
Table 10 shows the XtremCache deployment for the private cloud use case. The
configuration of the database LUNs follows the same best practices as the
application-specific use cases, such as source LUNs for XtremCache acceleration. We
excluded the log LUNs because they have mostly write and sequential I/O. We used
XtremSF in split mode for the DSS tempdb store to accelerate the DSS workload.
EMC VSPEX with EMC XtremSF and EMC XtremCache
Design Guide
85
Chapter 5: XtremCache Solution for Applications
Table 10.
XtremCache deployment in a private cloud environment
XtremCache allocation per
application/virtual machine
ESXi 01
(allocation unit:
GB)
ESXi 02
(allocation unit:
GB)
Configuration details
Oracle OLTP
600
0
2 TB database under 1,800
Swingbench sessions
DSS
0
200
2.5 TB database with DSS
workload
SQL OLTP 01
0
200
1.75 TB with OLTP
workload
SQL OLTP 02
0
200
1.12 TB with OLTP
workload
Total
600
600
Configuration of
XtremCache in the
VMware
environment
The configuration of XtremCache for a private cloud in a VMware environment needs
to follow all the guidelines for each individual application, such as SharePoint, SQL
Server, Exchange, and Oracle.
Test results
Test result for XtremSF in split mode used as the SQL Server tempdb for a DSS
workload
For more information, refer to the EMC XtremCache Installation and Administration
Guide.
In the solution, a 200 GB XtremCache was taken from the 700 GB XtremSF card and
was used for the tempdb database data and log storage to accelerate performance.
The SQL Server tempdb was heavily used as a temporary table store for sorting, row
versioning, and so on. As the tempdb store for a DSS workload, the XtremCache DAS
can:

Lower the peak latency of the tempdb data LUN from tens of milliseconds to
less than 20 ms.

Lower the average tempdb data LUN latency from tens of milliseconds to
one ms.
Test results for XtremCache deduplication
The test result shows:

The Oracle deduplication hit ratio was about 4 percent.

The SQL OLTP deduplication hit ratio was about 3 percent.
The recommended deduplication settings for a structured database such as Oracle or
SQL Server are:

86
If the observed ratio is less than 10 percent, turn off the deduplication or
reconfigure the deduplication gain to zero percent, to benefit from the extended
cache device life.
EMC VSPEX with EMC XtremSF and EMC XtremCache
Design Guide
Chapter 5: XtremCache Solution for Applications

If the observed ratio is over 35 percent, raise the deduplication gain to match
the observed deduplication.

If the observed ratio is between 10 and 35 percent, leave the deduplication
gain as it is.
Figure 46 shows that the deduplication hit ratio of SQL Server is 3 percent.
Figure 46. Deduplication statistics for SQL Server OLTP
Test results for two-tier storage
Table 11 shows the performance summary for the private cloud environment. For
Oracle, the response time dropped from 35 ms to 3 ms. For SQL Server, the response
time dropped from over 20 ms to 3 ms. All database transaction rates improved, with
the SQL Server OLTP gaining the most (which was a three times transaction rate
increase using part of the 700 GB caching space).
The increased CPU usage was largely due to the increased workload. When the
workload is kept the same or is not greatly increased, CPU usage does not increase
much. This is seen in the case of ESXi 01, which hosts Oracle—with only a moderate
increase in the workload, the CPU usage did not greatly increase.
EMC VSPEX with EMC XtremSF and EMC XtremCache
Design Guide
87
Chapter 5: XtremCache Solution for Applications
Table 11.
Component
Performance
Two tiers configured
without XtremCache
Two tiers configured
with XtremCache
SAN storage
Array IOPS
24,000
10,000
Busy%
60%
30%
ESXi 01
Avg. CPU utilization
16%
21%
ESXi 02
Avg. CPU utilization
2%
40%
Oracle OLTP
Swingbench Order Entry
(SOE) TPS
6,653
8,590
Swingbench Avg. Oracle
response (ms)
35
3
SQL01 Latency (ms)
read/write/transfer
22/4/21
3/2/3
SQL02 Latency (ms)
read/write/transfer
21/4/21
2/3/2
SQL01 vCPU utilization
1.20%
69.84%
SQL02 vCPU utilization
1.46%
63.04%
Client TPS (total)
56
162
TPS
2,073
6,054
SQL01
N/A
69%
SQL02
N/A
82%
SQL01
N/A
93%
SQL02
N/A
89%
SQL Server
XtremCache Hit Rate
XtremCache Read
Rate
88
Performance summary for the private cloud environment
EMC VSPEX with EMC XtremSF and EMC XtremCache
Design Guide
Chapter 5: XtremCache Solution for Applications
EMC VSPEX with EMC XtremSF and EMC XtremCache
Design Guide
89
Chapter 6: References
Chapter 6
References
This chapter presents the following topics:
EMC documentation ............................................................................................. 91
Other documentation ........................................................................................... 92
Links ................................................................................................................... 92
90
EMC VSPEX with EMC XtremSF and EMC XtremCache
Design Guide
Chapter 6: References
EMC documentation
The following documents, available from the EMC Online Support or EMC.com
websites, provide additional and relevant information. If you do not have access to a
document, contact your EMC representative.

EMC VNX Virtual Provisioning—Applied Technology

EMC VNX Series Unified Storage Systems—Specification Sheet

EMC VNX Family—Data Sheet

EMC Mission Critical Infrastructure for Microsoft SQL Server 2012—White Paper

EMC Storage Optimization and High Availability for Microsoft SQL Server 2008
R2 - EMC VNX5700, EMC FAST Suite, VMware vSphere 5—White Paper

EMC Mission Critical Infrastructure for Microsoft SQL Server 2012 - EMC
Symmetrix VMAX 10K, EMC FAST VP, SQL Server AlwaysOn Availability Groups,
VMware vSphere—White Paper

Accelerating Microsoft Exchange 2010 Performance with EMC XtremCache EMC VNX Storage and VMware vSphere—White Paper

EMC VFCache Accelerates Oracle - EMC VFCache, EMC Symmetrix VMAX and
VMAX 10K, Oracle Database 11g—White Paper

EMC VFCache Accelerates Virtualized Oracle - EMC VFCache, EMC Symmetrix
VMAX and VMAX 10K, VMware vSphere, Oracle Database 11g—White Paper

EMC VFCache Accelerates Oracle - EMC VFCache, EMC VNX, EMC FAST Suite,
Oracle Database 11g—White Paper

EMC VFCache Accelerates Microsoft SQL Server - EMC VFCache, EMC VNX,
Microsoft SQL Server 2008—White Paper

EMC VFCache Accelerates Virtualized Oracle - EMC VFCache, EMC Symmetrix
VMAX, EMC FAST Suite, VMware vSphere, Oracle Database 11g—White Paper
For additional information, visit the following spaces on EMC.com:

XtremCache

VNX Series
At the time of publication, the following related documents were available:

XtremCache Installation and Administration Guide v2.0.1

XtremCache Installation Guide for VMware 2.0.1

XtremCache Troubleshooting Guide 2.0.1

XtremCache Troubleshooting Guide for VMware v2.0.1

XtremCache VMware VSI Plug-in Guide 2.0.1

Introduction to EMC VFCache

EMC VFCache—Data Sheet

VFCache Installation and Administration Guide for Windows and Linux
EMC VSPEX with EMC XtremSF and EMC XtremCache
Design Guide
91
Chapter 6: References

VFCache Release Notes for Windows and Linux

VFCache Installation Guide for VMware

VFCache Release Notes for VMware

VFCache VMware Plug-in—Administration Guide

Considerations for Choosing SLC versus MLC Flash

EMC Storage Integrator for Windows Version 2.0.1—Product Guide

Microsoft Exchange 2010 on VMware—Best Practices Guide

VSI for VMware vSphere: Storage Viewer Version Product Guide 5.4
Other documentation
For additional Microsoft information, refer to the following articles:

SQL Server Best Practices

Tuning options for SQL Server when running in high performance workloads

Optimizing tempdb Performance

Microsoft Multipath I/O (MPIO) Users Guide for Windows Server 2012
For additional Oracle information, refer to the following documents:

Oracle Database Installation Guide11g Release 2 (11.2) for Linux

Oracle Database Release Notes for Linux
For additional VMware information, refer to the following document:

Installing EMC® XtremCache™ on ESXi 5.0 and 5.1
Links
For additional product information, visit the following websites:

VMware

Microsoft TechNet Library

MSDN Library

Oracle Database 11gR2 Documentation Library 11 g Release 2 (11.2)

Oracle Support website (for the latest OPatch and latest PSU)
Note: The links provided in this guide were working correctly at the time of publication.
92
EMC VSPEX with EMC XtremSF and EMC XtremCache
Design Guide
Chapter 6: References
EMC VSPEX with EMC XtremSF and EMC XtremCache
Design Guide
93
Appendix A: Ordering Information
Appendix A
Ordering Information
This appendix presents the following topic:
Ordering XtremSF and XtremCache ....................................................................... 95
94
EMC VSPEX with EMC XtremSF and EMC XtremCache
Design Guide
Appendix A: Ordering Information
Ordering XtremSF and XtremCache
XtremCache can be ordered through Direct Express and Channel Express. XtremCache
can be ordered by itself or in combination with XtremSF hardware. Use the following
model numbers when placing an order:
XtremCache

456-105-133 – ONE license for XtremCache (previously VFC-Software prior to
introducing e-licensing)

456-105-135 – a pack of FIVE licenses of XtremCache( UCS blades)
XtremSF

PCIEHHS-3XXM2 (350 GB, SLC)

PCIEHHS-7XXM (700 GB, SLC)

PCIEHHM-350M (350 GB, MLC)

PCIEHHM-550V (550 GB, MLC)

PCIEHHM-700M (700 GB, MLC)

PCIEHHM-1400M (1.4 TB, MLC)

PCIEHHM-2200V (2.2 TB, MLC)
EMC VSPEX with EMC XtremSF and EMC XtremCache
Design Guide
95