Availability Group Changes

Allan Hirt digs into SQL Server 2016 Availability Group changes:

What is a distributed availability group? Distributed availability groups allows you to create two different AGs on different Windows Server failover clusters (WSFCs) but join them together – if you will, an AG of AGs. This is great for disaster recovery scenarios where you do not want to worry (more than you should) about things like voters and quorum in a  single WSFC which could make the configuration more complex. This also allows for different versions of Windows Server (one WSFC is Windows Server 2012 R2 and another Windows Server 2016). Heck, it could even facilitate migrations to new hardware/the public cloud/virtualization assuming the same major version of SQL Server. It’s a cool feature. You can only manually fail over the AG between the WSFCs, but that’s OK, and you do need a listener for each AG. If you do not plan on using a listener, you cannot create a distributed AG.

Side note:  when I read DAG, I think directed acyclical graph.  Maybe I’m just weird that way…

Main note:  the idea of “seeding” an Availability Group sounds wonderful.

Related Posts

Lazy Log Truncation

Paul Randal explains why Virtual Log Files might remain in status 2 even after they are cleared: Earlier this year I was sent an interesting question about why the person was seeing lots of VLFs in the log with status = 2 (which means ‘active’) after clearing (also known as ‘truncating’) the log and log_reuse_wait_desc showed NOTHING. I […]

Read More

Removing A Database From An AG

Erin Stellato walks us through the process of removing a database from an Availability Group and then re-adding it later: I recently had a scenario in a two-node Availability Group where multiple large-batch modification queries were executed and created a large redo queue on the replica.  The storage on the replica is slower than that […]

Read More

Categories

March 2016
MTWTFSS
« Feb Apr »
 123456
78910111213
14151617181920
21222324252627
28293031