After adding the mailbox to the DAG, the server needs to be restarted

Question

Hello everybody!

There is a DAG on Exchange 2019 CU 12, I'm trying to add two mailbox servers to the DAG cluster. When you add the Add-DatabaseAvailabilityGroupServer -Identity DAG 03 -Mailbox Server MB 06 command, the server is added and the Failover Cluster role is being installed. I'm trying to add a second mailbox server to the cluster in the same way and I get an error. As it turned out, the source server requires a reboot - as far as I understood because of the cluster role. After that, he asks to add the mailbox to the cluster.

Can you tell me how to correctly add mailboxes to an existing DAG, that is, pre-install the Failover Cluster role?

Strange, but in the Exchange 2016 version I did not need to reboot the servers while adding mailboxes to the cluster, even when installing the Failover Cluster component, why is that?

Thanks!

Answer 1

Make sure the CNO has the right permissions:

https://learn.microsoft.com/en-us/exchange/high-availability/manage-ha/pre-stage-dag-cnos?view=exchserver-2019#assign-permissions-to-the-cno

Answer 2

I have never seen that. Its usually pretty seamless in all versions of Exchange. Are you sure there wasnt a pending reboot for something else?

Answer 3

I first installed all the components, rebooted, installed the Exchange product itself and also rebooted and so on after each installation of security updates and additionally before adding to the DAG.

That is, when adding to the DAG, the server installed the Failover Cluster role, and then I saw a delayed reboot in the Server Manager - I attached a screenshot.

Answer 4

Yea, strange. :(

According to the official docs, not reboot required for installing the Windows Pre-reqs neither, so maybe try that on the next server if you have adding another?

https://learn.microsoft.com/en-us/exchange/plan-and-deploy/prerequisites?view=exchserver-2019

Install-WindowsFeature Server-Media-Foundation, NET-Framework-45-Features, RPC-over-HTTP-proxy, RSAT-Clustering, RSAT-Clustering-CmdInterface, RSAT-Clustering-Mgmt, RSAT-Clustering-PowerShell, WAS-Process-Model, Web-Asp-Net45, Web-Basic-Auth, Web-Client-Auth, Web-Digest-Auth, Web-Dir-Browsing, Web-Dyn-Compression, Web-Http-Errors, Web-Http-Logging, Web-Http-Redirect, Web-Http-Tracing, Web-ISAPI-Ext, Web-ISAPI-Filter, Web-Lgcy-Mgmt-Console, Web-Metabase, Web-Mgmt-Console, Web-Mgmt-Service, Web-Net-Ext45, Web-Request-Monitor, Web-Server, Web-Stat-Compression, Web-Static-Content, Web-Windows-Auth, Web-WMI, Windows-Identity-Foundation, RSAT-ADDS

Answer 5

Hmm, strange, well, we rebooted the server only after installing the November SU and a framework like

That is, you want to say that if you do not follow the order of installing components or reboot earlier, then some roles may require additional reboots when added to the cluster?