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AlwaysOn Availability Groups 101
Using SQL Server 2012
About Me
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Jeff Reinhard
20 years database development experience
@jreiny
[email protected]
Employment Highlights:
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Ernst & Young
Internet Security Systems/IBM
AirWatch
WebMD
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Thank You
 Microsoft for the facility
 For sponsoring tonight’s event:
Pyramid Analytics
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Agenda
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What is AlwaysOn
Prerequisites
Setting Up
Monitoring
AlwaysOn and Your Application
Lessons Learned
Q&A
34 slides, so I need to move fast
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Two Types of AlwaysOn ???
 AlwaysOn Failover Cluster Instances
 leverages Windows Server Failover Clustering
(WSFC) functionality to provide local high
availability through redundancy at the serverinstance level—a failover cluster instance (FCI).
 Previously known as SQL Clusters
 Works with SQL Server Standard Edition
 AlwaysOn Availability Groups (AG)
 This presentation discusses further
 Requires SQL Server Enterprise Edition
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What Is AlwaysOn AG?
 AlwaysOn is SQL Servers best available technology for
SQL High Availability.
 AlwaysOn is a new integrated, flexible, cost-efficient high
availability and disaster recovery solution. It can provide
data and hardware redundancy within and across data
centers, and improves application failover time to increase
the availability of your mission-critical applications.
AlwaysOn provides flexibility in configuration and enables
reuse of existing hardware investments.
 The principal goal of a high availability solution is to
minimize or mitigate the impact of downtime.
 It is recommended for scenarios where high availability is
required and the application will benefit from readable
copies of the primary databases.
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AlwaysOn Architecture Overview
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Prerequisites – Before you begin
Prerequisites, Restrictions, and Recommendations for
AlwaysOn Availability Groups
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http://msdn.microsoft.com/en-us/library/ff878487.aspx
AlwaysOn Failover
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http://msdn.microsoft.com/en-us/library/ff929171.aspx
Do not use the Failover Cluster Manager to manipulate
availability groups, for example:
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Do not add or remove resources in the clustered service (resource group) for the availability
group.
Do not change any availability group properties, such as the possible owners and preferred
owners. These properties are set automatically by the availability group.
Do not use the Failover Cluster Manager to move availability groups to different nodes or to
fail over availability groups. The Failover Cluster Manager is not aware of the synchronization
status of the availability replicas, and doing so can lead to extended downtime. You must use
Transact-SQL or SQL Server Management Studio.
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Prerequisites – Before you begin (cont.)
AlwaysOn Quorum Resources
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http://blogs.msdn.com/b/sqlalwayson/archive/2012/03/13/quorum-vote-configuration-check-in-alwayson-availability-group-wizards-andyjing.aspx
http://msdn.microsoft.com/en-us/library/hh270280.aspx
http://msdn.microsoft.com/en-us/library/hh270281.aspx
http://technet.microsoft.com/en-us/library/cc770620(v=ws.10).aspx
Connecting with multi-subnet failover
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http://msdn.microsoft.com/en-us/library/hh205662.aspx
http://technet.microsoft.com/en-us/library/ff878716.aspx
Availability Group Listeners, Client Connectivity, and Application Failover (SQL Server) - http://technet.microsoft.com/enus/library/hh213417.aspx
Creating a listener
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http://technet.microsoft.com/en-us/library/hh213080.aspx
Prerequisites and requirements
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Only one listener can be created though SQL Server. If you need an additional listener, it can be created thought WSFC.
Recommendation, use a static IP for multiple subnet configurations.
You must be connected to the instance that hosts that primary replica
If using static IP addresses, the listener will have a static IP for each subnet that has a replica.
Configure Read-Only Routing for an AG
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http://technet.microsoft.com/en-us/library/hh710054.aspx
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Prerequisites - Windows Cluster
Go into Server Manager, features, add features
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Prerequisites - Windows Cluster (cont.)
Enable Failover Clustering
 Make sure cluster services are available on all
participating nodes
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Prerequisites - Windows Cluster (cont.)
 Add the database servers to the cluster
 Run validations, tests, etc.
 Some warnings are due to no storage available
to the cluster, which is correct for AlwaysOn.
 Create the cluster
 Create Active Directory computer account for
cluster name
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Prerequisites – SQL Server Configuration
 Open SQL Server Configuration Manager
 Select SQL Server Services, right click on SQL
Server, select properties
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AlwaysOn Set Up
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AlwaysOn Setup - Overview
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Working Primary Node
Available “blank slate” secondary
Create Availability Group
Select Databases
Specify Replicas
Create the AG Listener
Select full data synchronization
Run the wizard
Configure Read Only Routing
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AlwaysOn Setup - Working Primary Node
 Ensure your application is working properly
 Review logins and users and permissions
 Using Contained databases is recommended
but not required
 If not using contained databases, export the
logins
 http://support.microsoft.com/kb/918992
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AlwaysOn Setup - Available “blank slate”
secondary
 Secondary Node(s) should match the primary
in configuration, version, etc.
 Make sure the databases and files on the
primary do not exist on the secondary
 If not using contained databases, import the
logins used by the application.
 Don’t import default and windows authentication
accounts
 It is vital that the login SIDS match between the
primary and secondary node(s)
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AlwaysOn Setup - Create Availability Group
 Using SSMS, from your primary database
node, start the New Availability Group Wizard
and give it a name
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AlwaysOn Setup - Select Databases
 Select all of the databases that work together
as a set for your application; possibly
including Reporting Services database(s).
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AlwaysOn Setup - Specify Replicas
 The wizard will select your primary node, add
your secondary node(s)
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AlwaysOn Setup - Specify Replicas (cont.)
 For all, select Synchronous, Automatic
Failover, Readable Secondary = Yes
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AlwaysOn Setup - Create the AG Listener
 On the listener tab, enter name and port
1433, then click add for IP
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AlwaysOn Setup - Create the AG Listener
(cont.)
 Enter the IP address for the listener
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Select full data synchronization
 Create the folder, preferably on a secondary
node, then enter into the wizard
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Run the wizard
 Perform the validation, next, then finish to
create the AG
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Configure Read Only Routing
 I have a script that with the setting of a few
variables, will generate the code to perform
the configuration. Contact me and provide
payment if interested.
 http://www.sqlservercentral.com/scripts/AlwaysOn/116992/
 What is important after configuration
 Endpoint_url uses DNS name and port 5022
 Available mode is synchronous
 Failover mode is automatic
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Configure Read Only Routing (cont.)
 What is important after configuration (cont.)
 Primary role allow connections is ALL
 Secondary role allow connections is
READ_ONLY
 ReadOnly Routing URL is IP and port 1433
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AlwaysOn Monitoring - Dashboard
 The first place to start is the dashboard
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AlwaysOn Monitoring – Top Section
 Look for any errors, warnings, check that
failover mode is automatic, AG group state is
healthy, check the links on the right for any
errors or warnings
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AlwaysOn Monitoring - Replicas
 Check the health icon, failover mode is
automatic, synchronization state is good, and
no issues reported
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AlwaysOn Monitoring - Databases
 Check the primary and secondary, health
state, synchronization state, failover
readiness, issues
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AlwaysOn Monitoring (cont.)
 There are many DMV queries that can be
used
 Microsoft SQL Server 2012 AlwaysOn
Monitoring Management Pack
 AlwaysOn Availability Groups
Troubleshooting and Monitoring Guide
 http://technet.microsoft.com/enus/library/dn135328(v=sql.110).aspx
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AlwaysOn and Your Application
 The connection strings should all go to the
listener, not directly to any database server
instance
 To have your application use the primary
mode, no change is required in your
connection string
 To have your application use a readable
secondary, add to the connection string:
 ;ApplicationIntent=ReadOnly
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AlwaysOn Lessons Learned
 Request the DNS name and IP for windows
cluster and Availability Group Listener early, they
can take a while
 Research prerequisites, make sure all patches,
versions, components are optimal to support
AlwaysOn
 Schedule and plan out in advance, get key
players on board in the beginning
 Schedule implementation in two phases:
 Configuration of clusters, storage, SQL server stand
alone instances
 Implementation of AlwaysOn
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Bonus Trick
 Sometimes, when a database is in the state
of “not synchronizing”, and all other issues
have been resolved, running the below
command might get it back to healthy:
ALTER DATABASE [XXXXX]
SET HADR RESUME;
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Questions?
Thank
you for
your time!
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