Download ORACLE DATABASE HIGH AVAILABILITY

ORACLE DATABASE HIGH
AVAILABILITY
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OUTLINE
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Overview Of High Availability
Oracle Database High Availability Architecture
Determining Your High Availability Requirements
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OVERVIEW OF HIGH AVAILABILITY
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What is Availability ?
Availability is the degree to which an application,
service, or functionality is available upon user
demand.
Main characteristics of Availability:
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Reliability: system must have less errors in both
hardware and software – including database, web
servers, and application.
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OVERVIEW OF HIGH AVAILABILITY
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Recoverability: there may have many choices
in recovering from a failure. Hence, the most
appropriate action is also to satisfy business
requirements most
Timely error detection: although a system
can be recovered from an outage in time
manner, time to monitor corrupt components
can be costly and cause your SLA (service
level agreement) not met.
Continuous operation: maintenance
activities should be allowed to perform
continuous data access with little or no
downtime and transparent to end users.
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OVERVIEW OF HIGH AVAILABILITY
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Importance Of High Availability
Support enterprises to gain their competitive
advantages by providing capability of
continuously accessing to critical business data.
Much downtime (surpass the threshold) can
cause
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Direct cost: lost productivity, lost revenue.
Indirect cost: damaged customer relationships,
bad publicity, and lawsuits.
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OVERVIEW OF HIGH AVAILABILITY
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Causes Of Downtime
Unplanned:
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Computer failure
Storage failure
Human error
Data corruption
Site failure
Planned:
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System changes
Data changes
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OVERVIEW OF HIGH AVAILABILITY
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Causes Of Downtime
Unplanned:
Computer failure
A computer failure outage occurs when the system
running the database becomes unavailable because it
has shut down or is no longer accessible.
Example:
Database system hardware failure
Operating system failure
Oracle instance failure
Network interface failure
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OVERVIEW OF HIGH AVAILABILITY
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Causes Of Downtime
Unplanned:
Storage failure
A storage failure outage occurs when the storage
holding some or all of the database contents becomes
unavailable because it has shut down or is no longer
accessible.
Example:
Disk drive failure
Disk controller failure
Storage array failure
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OVERVIEW OF HIGH AVAILABILITY
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Causes Of Downtime
Unplanned:
Human error
A human error outage occurs when unintentional or
malicious actions are committed that cause data within
the database to become logically corrupt or unusable.
Example:
Dropped database object
Inadvertent data changes
Malicious data changes
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OVERVIEW OF HIGH AVAILABILITY
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Causes Of Downtime
Unplanned:
Site failure
A site failure outage occurs when an event causes all or
a significant portion of an application to stop processing
or slow to an unusable service level
Example:
Site-wide network failure
Natural disaster
Terrorist or malicious attack on operations or the
site
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OVERVIEW OF HIGH AVAILABILITY
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Causes Of Downtime
Planned:
System changes
Planned system changes occur when performing routine
and periodic maintenance operations and new
deployments.
Example:
Adding/removing processors to/from an SMP
server
Adding/removing nodes to/from a cluster
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OVERVIEW OF HIGH AVAILABILITY
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Causes Of Downtime
Planned:
Data changes
Planned data changes occur when there are changes to
the logical structure or physical organization of Oracle
database objects.
Example:
Table definition changes
Creating and rebuilding indexes
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ORACLE DATABASE HIGH AVAILABILITY
ARCHITECTURE
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Oracle Database 10g
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Oracle Flashback Technology
Automatic Storage Management
Recovery Manager
Flash Recovery Area
Online Reorganization and Redefinition
Oracle Database 10g with RAC
 Oracle Database 10g with Data Guard
 Oracle Database 10g with RAC and Data Guard –
MAA
 Oracle Database 10g with Streams
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STANDARD ORACLE DATABASE 10G
HIGH AVAILABILITY
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Oracle Flashback Technology
*The flashback features offer the capability to query past versions
of schema objects, query historical data, perform change analysis.
*Flashback technology includes the following features:
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Oracle Flashback Query
Oracle Flashback Versions Query
Oracle Flashback Transaction Query
Oracle Flashback Table
Oracle Flashback Drop
Oracle Flashback Database
Oracle Flashback Restore Points
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STANDARD ORACLE DATABASE 10G
HIGH AVAILABILITY
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Automatic Storage Management (ASM)
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ASM spreads files across all available storage and
mirror at the database file level rather than the entire
disk level.
ASM simplifies the processes of setting up mirroring,
adding disks, and removing disks
Instead of managing hundreds and possibly thousands
of files (as in a large data warehouse), DBAs using
ASM create and administer a larger-grained object—
the disk group—which identifies the set of disks that
will be managed as a logical unit.
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STANDARD ORACLE DATABASE 10G
HIGH AVAILABILITY
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Automatic Storage Management (ASM)
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With ASM mirroring, an additional level of data
protection can be provided with the use of failures
groups.
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STANDARD ORACLE DATABASE 10G
HIGH AVAILABILITY
ASM Mirroring Options
Mirroring Option
Description
2-way mirroring
Each extent has 1 mirrored copy.
3-way mirroring
Each extent has 2 mirrored copies.
Unprotected
ASM provides no mirroring. Used when
mirroring is provided by the disk subsystem
itself.
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STANDARD ORACLE DATABASE 10G
HIGH AVAILABILITY
Mirroring Options for Each Disk Group Type
Disk Group Type
Supported
Mirroring Levels
Normal redundancy
Default Mirroring
Level
2-way
2-way
3-way
Unprotected (none)
High redundancy
3-way
3-way
External
redundancy
Unprotected (none)
Unprotected
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STANDARD ORACLE DATABASE 10G HIGH
AVAILABILITY
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Recovery Manager
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Recovery Manager is an Oracle utility to manage the
backup and, more importantly, the recovery of the
database.
RMAN provides the following benefits:
• Automatic failover to a previous backup when the restore
operation discovers a missing or corrupt backup.
• Automated recovery through a previous point-in-time
recovery.
• Fast incremental backups using block change tracking.
• Retention policy ensures that relevant backups are
retained
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STANDARD ORACLE DATABASE 10G
HIGH AVAILABILITY
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Flash Recovery Area
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The flash recovery area is a unified storage location
for all recovery-related files and activities in an
Oracle database.
All RMAN backups, archive logs, control file
autobackups, and datafile copies are automatically
written to a specified file system or ASM disk group.
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STANDARD ORACLE DATABASE 10G
HIGH AVAILABILITY
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Online Reorganization and Redefinition
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One way to enhance availability and manageability is
to allow users full access to the database during a
data reorganization operation.
Online architecture provides the following benefits:
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Tables can be reorganized and redefined online:
any physical or logical attribute of the table can
be changed online.
All index operation can be performed online
Online move of a partitioned table.
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ORACLE DATABASE 10G WITH RAC
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Oracle Database 10g with RAC architecture uses
Real Application Clusters and is an inherently
high availability system
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ORACLE DATABASE 10G WITH RAC
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This architecture provides the following benefits:
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Fast node (measured in minutes) and instance
failover (measured in seconds)
Rolling patch upgrades
Multiple active instance availability and scalability
across multiple nodes
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ORACLE DATABASE 10G WITH DATA GUARD
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Data Guard provides a comprehensive set of
services that create, maintain, manage, and
monitor one or more standby databases to enable
Oracle databases to survive disasters and data
corruption.
Two type of standby databases:
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Physical standby database
Logical standby database
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ORACLE DATABASE 10G WITH DATA GUARD
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Physical standby database provide these advantages:
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Protection from user errors and logical corruption
Protection from disasters and site failures if located
remotely
Standby database can diverge for reporting or
testing purposes and resynchronize with its primary
database once complete
Backups can be taken from the physical standby
database instead of the production database,
relieving the load on the production database
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ORACLE DATABASE 10G WITH DATA GUARD
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Logical standby database provide these advantages:
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A logical standby database can be used for other
business purposes in addition to disaster recovery.
Users can access a logical standby database for
queries and reporting purposes.
Enable rolling database upgrades of the production
database
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ORACLE DATABASE 10G WITH DATA GUARD
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ORACLE DATABASE 10G WITH RAC AND
DATA GUARD – MAA
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RAC and Data Guard provide the basis of Oracle
Database 10g – Maximum Availability Architecture
(MAA).
Symmetric sites also enable processes and procedures
to be kept the same between sites, making operational
tasks easier to maintain and execute.
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ORACLE DATABASE 10G WITH RAC AND
DATA GUARD – MAA
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ORACLE DATABASE 10G WITH STREAMS
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Oracle Database 10g with Streams provides
granularity and control over what is replicated and
how it is replicated.
It supports bidirectional replication, data
transformations, custom apply functions, and
heterogeneous platforms
It supports different character sets between the
primary database and its replicas.
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ORACLE DATABASE 10G WITH STREAMS
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DETERMINING YOUR HIGH AVAILABILITY
REQUIREMENTS
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Analysis Framework for Determining High
Availability Requirements
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Business Impact Analysis
Cost of Downtime
Recovery Time Objective (RPO)
Recovery Point Objective (RTO)
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DETERMINING YOUR HIGH AVAILABILITY
REQUIREMENTS
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High Availability Architecture Requirements
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Service level agreements (SLAs) can categorize
businesses into several high availability tiers:
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Tier 1 business processes have maximum business
impact. They have the most stringent high availability
requirements, with RTO and RPO close to zero.
Tier 2 business processes can have slightly relaxed
high availability and RTO/RPO requirements.
Tier 3 business processes may be related to internal
development and quality assurance processes.
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DETERMINING YOUR HIGH AVAILABILITY
REQUIREMENTS
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Planning and Implementing a Highly Available Enterprise
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ORACLE HIGH AVAILABILITY SOLUTIONS
FOR UNPLANNED DOWNTIME
Outage Type
Oracle Solution
Computer failures
Fast-Start Fault Recovery
RAC
Data Guard
Oracle Streams
Storage failures
ASM
RMAN with flash recovery area
Data Guard
Oracle Streams
Human errors
Oracle security features
Oracle Flashback technology
LogMiner
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ORACLE HIGH AVAILABILITY SOLUTIONS
FOR UNPLANNED DOWNTIME
Outage Type
Oracle Solution
Data corruption
HARD
RMAN with flash recovery area
Data Guard
Oracle Streams
Site failures
RMAN
Data Guard
Oracle Streams
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ORACLE HIGH AVAILABILITY SOLUTIONS
FOR PLANNED DOWNTIME
Outage Type
Oracle Solution
System changes –
Dynamic Resource
Provisioning, Rolling
Upgrades
Oracle Database 10g
RAC
Data Guard
MAA
Oracle Streams
Data changes Online
Reorganization and
Redefinition
Oracle Database 10g
RAC
Data Guard
MAA
Oracle Streams
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