SQL SERVER – Migrating AlwaysOn Availability Group to New AD Domain

As a part of my independent consulting, I also provide a high level overview of the migration strategy. As a part of this engagement, my client wanted me to provide steps to move AlwaysOn availability group from DomainOld to DomainNew. This was happening because they were acquired by another company and they need to migrate all assets to a new domain.

Topology

Here are the steps which I told them.

• Remove replica Node-03 from availability group.
• Evict Node-03 from the windows cluster.
• Since Node-03 is completely out of AG, we can rebuild Node-03 in DomainNew
• Create a new windows cluster having just one node Node-03.
• Use scripts to migrate all server level objects – logins, jobs, operators from Node-01 to Node-03.
• Node-02 also needs same steps as Node-03 with one difference that it would be part of the same cluster as Node-03 rather than new cluster.
• Configure database mirroring for user databases from Node-01 to Node-03.
• OUTAGE: failover mirror databases to Node03, break the mirror and point application to Node-03.
• Perform test and test and test.
• Evict Node-01 and decommission the original cluster.
• Rebuild Node-01 in the new domain and add it to the cluster.
• Backup and restore the database from the Node-03 to the two new nodes and implement AG across all three new nodes.

After getting above high level guidance, they executed the project and it went fine.

Hope this step would help others as well about AlwaysOn Availability Group.

Reference: Pinal Dave (https://blog.sqlauthority.com)