Building Always On, Part 2

AlwaysOn Availability Groups will replace mirroring as a disaster recovery option starting with SQL Server 2012, and where applicable should be used as the primary DR option in SQL 2012 installs. This post will cover the configuration process for Availability Groups.

SQL Server Failover Cluster Instances may be members of on Availability Group (automatic failover is not an option in that model), this document will cover the configuration using standalone instances. The configuration is nearly the same for Availability Groups involving FCIs as members.

Prerequisites:

1. Windows is installed and all servers are members of the same domain
   
2. The Windows failover cluster is build and all servers marked for installation are members of that cluster
   
3. An AD virtual computer object and IP address have been reserved for the Listener which will control connectivity to the Availability Group.
   

Steps:

1. Install SQL Server on each node (using standard installation process, for either cluster or standalone)
   
2. There are two options for enabling SQL AlwaysOn Availability Groups. The first is via PowerShell. Launch PowerShell (as Administrator)
   

Issue the following commands:

–sqlps (imports the SQL Powershell modules)

–cd sql\$instancename\default

–enable-sqlalwayson -ServerInstance $Instancename -Force

 Note–this causes a restart of the SQL instance. The service must be restarted for SQL AlwaysOn to be enabled.

 The other option is to go into SQL Server Configuration Manager and right click on the SQL Server service. Click on the AlwaysOn High Availability tab.

Click the check box to enable AlwaysOn. The Database server is now ready for AlwaysOn configuration.