November 8, 2019 at 9:08 am
Hello crowd,
I found a couple of threads with upgrade discussions, but not what I was searching for.
I'm planning to upgrade my SQL2014 Always On HA Cluster from W2k12 R2, SQL2014 to Win2k16, SQL2017.
In my Test Environment I added the 2 new Win2k16 nodes with SQL2017 to the Cluster, then joined one of ther new hosts to the HA group. I switched the HA group with the test databases to the new SQL2017 instance.
It seems to work, the HA group and databases are running on the 2017 Instance, but is this supported.
Or do I expect any issues with this migration path?
Thx for your feedback.
Cheers
November 9, 2019 at 9:10 am
Thanks for posting your issue and hopefully someone will answer soon.
This is an automated bump to increase visibility of your question.
November 15, 2019 at 9:37 pm
Hi DBASam, about a year ago, I went through almost the same upgrade Win2012, SQL 2014 AOAG 2 Replicas to Win2016 SQL 2016.
I ended up getting so guidance from Microsoft to make sure we were going in the right direction.
Consideration # 1 - When you do your failover to your SQL 2017, you will not be able to fail back nor replicate back to the SQL 2014 instance. There is no downgrade possible. Just plan accordingly and make plenty of backups of your SQL 2014 database so you can Come back to the last known good version.
Consideration #2 - When you add a Windows 2016 to a Windows 2012 cluster, the 2016 will be in "Compatibility Mode" there will not be any of the 2016 features. After you've done your failover to the new Replica's on Windows 2016, Before you can upgrade the Cluster to the Native 2016 Cluster, you will need to evict ALL old nodes to be able to upgrade it. To upgrade the cluster, all you do it run this command in Powershell:
Update-ClusterFunctionalLevel -Cluster "ClusterName"
Hope this helps !
November 18, 2019 at 9:43 am
As already stated, this is a one-way upgrade. You can fail over to a higher version but you can't fail back to a lower one. As long as you have a plan for removing those SQL 2014 nodes cleanly you should be fine.
November 18, 2019 at 12:00 pm
Hello poupster2 and Beatrix,
Thanks for your answers, good to now that it will work.
My idea was to go this way, to have as less downtime as possible.
Now for production i built a new AOAG Cluster and I guess I will do it with backup/restore applications one by one.
cheers
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