How to install CU Rollups and Service Packs on DAG Members

Special procedures are required when installing Update Rollups, Cumulative Updates (CU) and Service Packs on an Exchange DAG environment.

Steps for installing Update Rollups, CU and Service Packs on an Exchange DAG:

• Before we start, lets make sure your databases are in a healthy state and review which server they are active on, run “get-mailboxdatabasecopystatus *” from the Exchange Management Shell (EMS).
• If you are installing Exchange 2013 SP1 then you need to first prepare the Schema and AD for Exchange 2013 SP1.

1) Open Exchange Management Shell (EMS)
2) Move-ActiveMailboxDatabase -Server EXCHANGESERVERBEINGUPDATED
Note: if you have move than 7 or 8 databases then I would Move them one by one, otherwise sometimes a bunch will get stuck in fail status for awhile when to many are moved at once: Move-ActiveMailboxDatabase DB1 -ActivateOnServer EXCHANGESERVERNOTBEINGUPDATED
3) cd “Program Files\Microsoft\Exchange Server\V14\Scripts”
4) .\StartDagServerMaintenance.ps1 –serverName EXCHANGESERVERBEINGUPDATED
5) Install the rollup.  Follow the steps in this link, the best way to install an Exchange Rollup
6) Reboot the server after the successful rollup installation.  Wait a few minutes for the servers to get sorted, and run “get-mailboxdatabasecopystatus *” from the Exchange Management Shell to make sure the databases are in a healthy state.
7) End the DAG maintenance on the server that you updated in the previous steps: .\StopDagServerMaintenance.ps1 -serverName EXCHANGESERVERNAME1
Re-run “get-mailboxdatabasecopystatus *” to make sure everything is healthy
8) repeat steps 1 through 7 to update the remaining DAG members

9) Redistribute the active databases per your set activation preferences:
.\RedistributeActiveDatabases.ps1 -DagName <DAG1> -BalanceDbsByActivationPreference -ShowFinalDatabaseDistribution -Confirm:$false

Good commands to test replication health along the way and when you are finished:
Test-ReplicationHealth –identity EXCHANGESERVERNAME1
Test-ReplicationHealth –identity EXCHANGESERVERNAME2
get-mailboxdatabasecopystatus *

References:

https://technet.microsoft.com/en-us/library/ee861125.aspx

More information on Dag Maintenance Scripts: https://www.mikepfeiffer.net/2010/08/performing-maintenance-on-dag-members-in-exchange-2010-sp1/