1 windows failover cluster and 4 Availability groups, is it possible?

  • Hello,

    I am trying to verify if possible to have 1 fail over cluster, but 4 availability groups, is it possible? what i am trying to accomplish is this:

    Database servers will be 1 instance per server, there is a total of 3 server, each one that has 1 database that will act as primary, but the other 2 will be secondary, etc. etc, example below:

    server 1                                  server 2                           server 3
    primary database1                  secondary database1        secondary database1
    secondary database2             pimary database2              secondary database2
    secondary database3             secondary database3         piamary database3

    also, the primary will obvious be read and write etc., is this possible under one fail over cluster, but multiple availability groups?

    thanks in advance

  • Yes, that's absolutely fine.

  • Thanks SSCommitted, one last thing to ask... has anyone ever installed multiple instances on 1 cluster, example:

    All one Server

    Server1
    InstanceA
    InstanceB
    InstanceB

    And I am informed this server1 is really beefy, but, wondering if this is possible:

    Server1                      Server2
    InstanceA      AG1      InstanceA
    InstanceB      AG2      InstanceB
    InstanceB     AG3      InstanceC

    So thinking both instances would belong to 1 Windows Fail over cluster, would that work?

    thanks for any feedback/thoughts.

  • Siten0308 - Tuesday, March 7, 2017 7:51 AM

    Thanks SSCommitted, one last thing to ask... has anyone ever installed multiple instances on 1 cluster, example:

    All one Server

    Server1
    InstanceA
    InstanceB
    InstanceB

    And I am informed this server1 is really beefy, but, wondering if this is possible:

    Server1                      Server2
    InstanceA      AG1      InstanceA
    InstanceB      AG2      InstanceB
    InstanceB     AG3      InstanceC

    So thinking both instances would belong to 1 Windows Fail over cluster, would that work?

    thanks for any feedback/thoughts.

    just remember that a single database can only be part of one AG

    -----------------------------------------------------------------------------------------------------------

    "Ya can't make an omelette without breaking just a few eggs" 😉

  • Perry is right, but other than that, having multiple instances on one server seems to be a matter of preference. Some DBAs love it, some hate it and would rather use multiple VMs instead. Some pros and cons here:

    https://www.brentozar.com/archive/2016/12/install-multiple-instances-sql-server/ 

  • Yup, it's possible.  I've worked in the past with a server setup as you describe running six AGs containing around 550 DBs between them...

    Thomas Rushton
    blog: https://thelonedba.wordpress.com

  • ThomasRushton - Wednesday, March 8, 2017 4:04 AM

    Yup, it's possible.  I've worked in the past with a server setup as you describe running six AGs containing around 550 DBs between them...

    wow, thread usage must be a killer.
    I'd love to see the failover time for those AGs
    TempDB must have been huge just maintaining the secondary stats for any readable secondarys

    -----------------------------------------------------------------------------------------------------------

    "Ya can't make an omelette without breaking just a few eggs" 😉

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