Updating to latest CU in a cluster with a bunch of databases.

Can I do this on the passive node without SQL Server kicking on? Do I need to worry about that?

I think I can run it on the passive, reboot the passive, then failover and ... at this point I'm unsure what happens with the databases in the instance.

Does it go through and update each individual database?

Run update exe on passive node

Reboot passive node



1 Answer 1


Install the CU on a passive node, failover, install on another passive node, repeat until all nodes are patched.

When you failover to the passive node, the databases will be upgraded. If you failback, the databases will be downgraded back to the old CU. (This is true for CU's, not for SP's or Major Version upgrades).

  • Hey, thanks for the feedback on this I really appreciate it. Do I have to worry about SQL Server kicking on during any of this on the passive nodes? Just trying to make sure I don't miss any steps. We're moving up like five cu's from where we are now Jul 15, 2020 at 20:07
  • no, it won't do anything strange. Jul 15, 2020 at 20:57
  • In addition to this, you should remove the server you're patching from being a possible failover partner while the CU installs. In the event there's a failover during install, this can result in your instance being unable to start, and forcing you to repair the install and restore system databases.
    – AMtwo
    Jul 16, 2020 at 3:53
  • Thank you again for the info and feedback this is super useful. Unfortunately, it's a two node cluster, so it's my only partner. Jul 16, 2020 at 13:16

Not the answer you're looking for? Browse other questions tagged or ask your own question.