As I’ve written before, Microsoft has made significant strides on making Active Directory Domain Controllers safe(r) to virtualize in Windows Server 2012. Sometimes, however, you encounter a situation that makes all that progress seem to disappear. Microsoft, last week, has released KnowledgeBase Article 2853952, describing such a situation.
In KnowledgeBase Article 2853952, Microsoft describes the situation where the Active Directory database may become corrupted, when you have a Windows Server 2012-based virtualized Active Directory Domain Controller on a Windows Server 2012-based Hyper-V host server and the Hyper-V host server crashes or encounters a power outage.
This issue occurs because the guest system requests the Hyper-V server to turn off disk caching on a disk. However, the Hyper-V host server misinterprets the request and keeps disk caching enabled.
To resolve this issue, install update rollup 2855336 on the Windows Server 2012-based Hyper-V host server. This update is part of the 2855336 Update for Windows RT, Windows 8, and Windows Server 2012 update rollup: July 2013.