Best way to reinstall Exchange 2016

Question

Hi,

We have 2 exchange server configured in DAG.
Servers have different build numbers (server one build 15.1.2242.4, server two build 15.1.2375.7).
Both exchange servers functional but due third party software error we must reinstall OS on server one, we also would like to equalize the build versions.

We consider two scenario:
Scenario 1: exclude server one from DAG, reinstall OS and recover server (via setup with /m:RecoverServer parameter) with CU 22 (build 15.1.2375.7) installer and readd it to DAG.
Scenario 2: remove server one from DAG, uninstall exchange (via setup with /m:Uninstall parameter), reinstall OS, install new Exchange instance with target version, add it to DAG.

I found information I can recover server only to the same build it was previously. Is it true?

Which scenario in your opinion is best?

Answer 1

Hi @Mariusz Gora ,

Agree with andy.

I would also select the Scenario 2. I think it's a good decision to start over with a clean system.

“I found information I can recover server only to the same build it was previously. Is it true?”

You can recover a server using the latest available Cumulative Update.

You could get more details about recover exchange server. Please check this document.
https://learn.microsoft.com/en-us/exchange/high-availability/disaster-recovery/recover-exchange-servers?view=exchserver-2019

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Answer 2

IF I had a choice, Scenario 2.

That way you start clean,.

RecoverServer is intended for DR scenarios where the server is lost.

Answer 3

The first option looks faster. It also gets rid of the new high availability group setup.

Why do you recommend the second option? I do not see the pluses in the second option. The first option looks more optimized.