sql server cluster and ag node

  • Looking at building solution for our 2016 claims dept.  Was considering one of two options below (all of this on VMware and sql 2016 enterprise edition)

    1. Build active passive cluster and one AG with read only node
    2.Build AG with 2 sql instances failover other node as read only

    Any opinions

  • tcronin 95651 - Tuesday, May 1, 2018 7:43 AM

    Looking at building solution for our 2016 claims dept.  Was considering one of two options below (all of this on VMware and sql 2016 enterprise edition)

    1. Build active passive cluster and one AG with read only node
    2.Build AG with 2 sql instances failover other node as read only

    Any opinions

    Quick question, why 2016 and not 2017, lots of improvements in the latest version?
    😎

  • not supported by vendor this is 3rd party app

  • Quick question may be if I setup AG with 2 servers with one read only intent, and primary fails, can it fail over to Read only intent?  If so when primary comes back online can they reverse roles?

  • tcronin 95651 - Tuesday, May 1, 2018 7:43 AM

    Looking at building solution for our 2016 claims dept.  Was considering one of two options below (all of this on VMware and sql 2016 enterprise edition)

    1. Build active passive cluster and one AG with read only node
    2.Build AG with 2 sql instances failover other node as read only

    Any opinions

    Theyre not separate options, theyre the same.
    If you build a 2 node cluster you will need 2 sql server instances to support an AG.

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

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

  • tcronin 95651 - Tuesday, May 1, 2018 9:12 AM

    Quick question may be if I setup AG with 2 servers with one read only intent, and primary fails, can it fail over to Read only intent?  If so when primary comes back online can they reverse roles?

    The other node will become the primary (R/W) replica.

    Check that you are covered for licensing because there can be licensing implications for using both nodes (but not always, so it depends on your company's individual agreement).

  • all on vmhosts so license not an issue we are set at host levle

  • Cool you should be ok then. You''ll need to specifically configure read-only routing, by the way. It's not as simple as just enabling the read-only attribute within the AG. (Sorry if that seems obvious, but a lot of people miss it.)

    https://docs.microsoft.com/en-us/sql/database-engine/availability-groups/windows/configure-read-only-routing-for-an-availability-group-sql-server?view=sql-server-2017

  • if I go with #2 is it possible to have a AG with 2 nodes (one as failover and read only intent).  If so if server A fails over can server B become primary and when A comes back it takes over as read only intent?

  • Yes. Or you can set it so that whenever either A or B is the primary, the other one is read-only, so they can fail over quite happily with minimal intervention from you. You'll need to use a listener to route the connections to the right place.

  • I am correct that the app has to use a readonly intent for connections?

  • tcronin 95651 - Thursday, May 3, 2018 6:08 AM

    if I go with #2 is it possible to have a AG with 2 nodes (one as failover and read only intent).  If so if server A fails over can server B become primary and when A comes back it takes over as read only intent?

    1 is 2 and 2 is 1, unless of course there's some detail you've left out.
    Please read my stairway to alwayson starting at this link

    http://www.sqlservercentral.com/stairway/112556/

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

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

Viewing 12 posts - 1 through 11 (of 11 total)

You must be logged in to reply to this topic. Login to reply