Installing Update Rollups on Database Availability Group Members
Although it’s documented on our TechNet however I always receive a question for how to install a RU on DAG members, so to make it easier here is the simple steps to do so:
- Use the StartDagServerMaintenance.ps1 script to put the DAG member in maintenance mode
- Install the update rollup
- Use the StopDagServerMaintenance.ps1 script to take the DAG member out of maintenance mode and put it back into production
- Use the RedistributeActiveDatabases.ps1 script to re-balance the active database copies across the DAG
The StartDagServerMaintenance.ps1 performs the following tasks:
- It runs Suspend-MailboxDatabaseCopy for each database copy hosted on the DAG member.
- It pauses the node in the cluster, which prevents it from being and becoming the PAM.
- It sets the value of the DatabaseCopyAutoActivationPolicy parameter on the DAG member to Blocked.
- It moves all active databases currently hosted on the DAG member to other DAG members.
- If the DAG member currently owns the default cluster group, it moves the default cluster group (and therefore the PAM role) to another DAG member
The StopDagServerMaintenance.ps1 performs the following tasks:
- It run Resume-MailboxDatabaseCopy for each database copy hosted on the DAG member.
- It resumes the node in the cluster, which it enables full cluster functionality for the DAG member.
- It sets the value of the DatabaseCopyAutoActivationPolicy parameter on the DAG member to Unrestricted.
Hope that this helps