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New Post has been published on http://www.varindersandhu.in/2014/05/27/sql-server-alwayson-availability-groups/
SQL Server - AlwaysOn Availability Groups
Microsoft introduced the AlwaysOn Availability Groups which is a high-availability and disaster-recovery solution that provides an enterprise-level solution in SQL Server 2012.
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Using Database Mirroring for local high availability and combining it with Log Shipping for a disaster recovery solution is popular deployment architecture prior to SQL Server 2012. With SQL Server 2012, the Database Mirroring and Log Shipping solution can be replaced with an Availability Group solution with multiple secondaries.
AlwaysOn Availability Groups – Deployment Architecture
SQL Server – AlwaysOn Availability Groups
The whitepaper http://msdn.microsoft.com/en-us/library/jj191711.aspx provides architecture details and best practices for this solution.
Enhancement to SQL Server 2014 AlwaysOn Availability Groups
Enhanced Availability for Read-Only Replicas: With SQL Server 2014, read workloads not impacted during network failures (or primary down, or cluster quorum loss). Also secondary replicas can be used for reporting and backup.
Increased Number of Replicas: Maximum number of secondaries increased from 4 to 8 (but Max 2 sync secondaries for high availability)
Add Azure Replica Wizard: On-premises SQL Server instances can use the new Windows Azure configuration options in the AlwaysOn Availability Group wizard to create one or more asynchronous secondary replicas on Windows Azure Infrastructure as a Service (IaaS) services.
Enhanced Diagnostics: SQL Server 2014 AlwaysOn Availability Groups diagnostic and troubleshooting message display has been improved.
Comparison of Failover Cluster Instances and Availability Groups
Description Nodes within an FCI Replicas within an availability group Uses WSFC cluster Yes Yes Protection level Instance Database Storage type Shared Non-shared Storage solutions Direct attached, SAN, mount points, SMB Depends on node type Readable secondaries No Yes Applicable failover policy settings
Availability group settings
Availability group settings
Failed-over resources Server, instance, and database Database only
Watch Video on “AlwaysOn in Microsoft SQL Server 2014″: http://channel9.msdn.com/events/TechEd/NorthAmerica/2014/DBI-B332#fbid=
