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Why can't you upgrade the version of Windows Server on an Exchange Server?

Is this a valid limitation as of today? For example, suppose you're running Windows Server 2012 and want to upgrade to 2012 R2 and Exchange Server 2013.

I know that the best practice is to get new hardware, install the new operating system and then Exchange Server. But moving the mailboxes and checking if everything is fine is painfully slow work, and in the most cases it's not a viable option.

p.s.w.g
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Vinícius Ferrão
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1 Answers1

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Microsoft does not support upgrading the OS for Exchange Servers.

Assuming you have DAGs setup, it's reliance on fail-over clustering with Windows will be one of the biggest issues with trying to upgrade the OS. Windows 2012 R2 to the soon-to-be released new Windows Server version is the first version to allow upgrades to the OS for Windows Fail-over Clusters.

Beyond that, there is still a lot of intertwining with Exchange and the various windows components in the OS. Some of those components change significantly from version to version (IIS 6 is VERY different from IIS7 for instance, service dependencies for services that don't exist or renamed in later versions) and trying to upgrade those components that Exchange users and taking into account any various customization/changes/3rd party components that integrate with previous versions, etc make make it essentially impossible to upgrade the OS from underneath Exchange.

An (older) example of someone trying to upgrade Windows 2003 to 2008 with Exchange 2007 can be found here. While older, the general idea remains the same.

It doesn't work.

edit: Moving 900GB of mail and 10 databases isn't actually that hard. Assuming you are going from Exch2007+ to 2013, you can move them online. Use batch moves to stage the mailboxes and finalize at your convenience. Throttling can be used to ensure performance if your underlying systems are taxed.

Rex
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  • Actually we aren't using DAGs. So the failover question isn't really an issue. And I already have Windows Server 2012 with Exchange Server 2013 CU9 running. I just want an R2 Upgrade. – Vinícius Ferrão Jul 20 '15 at 22:38
  • Rex, I'm giving you the answer, but take a look at my question about not using Failover Clustering. – Vinícius Ferrão Jul 22 '15 at 20:50
  • Failover clustering is the only hard blocker. The other issues on dependencies on System level components and possible 3rd party interoperability issues still stand as soft blockers. – Rex Jul 23 '15 at 14:57