Availability Groups And VMs

John Martin looks at combining Availability Groups with a virtualized environment:

Much of the time there is a systems team and a DBA team, and when the DBAs need to build out a new set of SQL Servers, they request X number of virtual servers from the systems team. The servers are handed over and the DBA team works its magic, and then we have our Failover Cluster Instance or Availability Group High Availability solution. But, is it really Highly Available?

The reason I ask is twofold:

  • Which physical hosts are your Virtual Machines are located on?
  • Which data stores are your virtual disks are located in?

If the answer to either of these questions results in the same answer for any of your Virtual Machines in an Availability Group, or Failover Cluster Instance for that matter. Then you potentially have a massive flaw in your implementation that can affect availability.

The moral of the story is to communicate with the network administrators and SAN folks.

Related Posts

Oddity With User Write Count In dm_db_index_usage_stats

Shaun J. Stuart looks at an oddity with the user_updates column on sys.dm_db_index_usage_stats: This pulls both reads and writes from the sys.dm_db_index_usage_stats dynamic management view. A read is defined as either a seek, scan, or lookup and a write is defined as an update. All seemed good until I noticed something strange. One of the top written to tables was, based on our naming convention, a […]

Read More

Safely Dropping Databases

Bob Pusateri notes a little issue when it comes to dropping databases: At a previous employer, we had a well-defined process when dropping databases for a client. It went something like this: Confirm in writing the databases on which servers/instances to be dropped Take a final full backup of databases Take databases offline Wait at […]

Read More

Categories

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