December 2, 2018 at 9:37 am
Hi,
I have an sql server cluster.I am planning an upgrade and I read that rolling upgrade is suggested method for cluster upgrade.
If I pick current passive node and upgraded to new version..Then I should do testing..this needs a fail over to passive node(upgraded node)from current active.
At this stage all databases will be converted to new version..So what is the rollback process in this ?I assume I cant just fail back to the non upgraded node, since old node is in old version..but all databases are in new version and a degrade will not happen.
Can Some one pls advice , whether my understanding is correct?
In this case rolling upgrade is not a safe way, and best option is create another cluster and restore there?
thanks
davis
December 3, 2018 at 5:05 am
You don't say what you're upgrading from and to, but don't do an in-place upgrade in Production without at least testing it elsewhere first. (In fact I'd say don't do an in-place upgrade at all, but nobody likes to hear that). Ideally build new hardware and migrate your databases over. Depending on your existing OS you may need to upgrade it anyway.
December 3, 2018 at 1:25 pm
I concur, in place upgrade is not good idea, be prepared to deal with lots of issues in future if you go this route.
December 3, 2018 at 3:27 pm
sdavis754 - Sunday, December 2, 2018 9:37 AMHi,
I have an sql server cluster.I am planning an upgrade and I read that rolling upgrade is suggested method for cluster upgrade.
If I pick current passive node and upgraded to new version..Then I should do testing..this needs a fail over to passive node(upgraded node)from current active.
At this stage all databases will be converted to new version..So what is the rollback process in this ?I assume I cant just fail back to the non upgraded node, since old node is in old version..but all databases are in new version and a degrade will not happen.
Can Some one pls advice , whether my understanding is correct?In this case rolling upgrade is not a safe way, and best option is create another cluster and restore there?
thanks
davis
I have performed an in-place upgrade on a cluster before - upgrading from SQL Server 2008 R2 to SQL Server 2012. Prior to performing this upgrade in production on the cluster - we upgraded the test system and validated the application worked as expected on the new version.
At that point - the decision has been made to upgrade to the new database version there isn't a rollback plan. If the upgrade fails on the non-active node for any reason we never fail over to that node and the rollback is to rebuild the failed upgrade node back to the current version. If the upgrade is successful - we fail over to the upgraded node, upgrading the databases - at which point you are live on the upgraded version.
If the idea is to upgrade - test the application - and then roll back to a prior version if the application has issues - the only way that is going to be possible is to insure you take backups prior to starting the upgrade and get ready to rebuild the cluster instance(s). That would require removing SQL Server from all nodes - reinstalling SQL Server at the correct version - restoring database backups (and rebuilding logins, agent jobs, database maintenance, etc...) and then testing and validating that everything is working as expected.
In short - the best option is to build out a new cluster...test and validate as thoroughly as possible - then schedule a migration from old cluster to new cluster. This requires a process to backup the databases/logins/agent jobs/etc...restore/apply to new cluster and then update all connections from clients/servers to the new cluster. Generally - if possible - it is less work to actually build out a full new environment that includes all application servers. At cutover - you shut down the old systems - migrate the databases from old to new - redirect end users to new application servers - and release...
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