Monday, November 1, 2010

The Resource Hosting Subsystem (Rhs.exe)...

Today I added my fourth node to my Windows Server 2008 R2 Cluster.

The cluster validation reported none errors, and I was about to Live Migrate one VM over to this new node.

It resulted in the following error:
The cluster resource host subsystem (RHS) stopped unexpectedly. An attempt will be made to restart it. This is usually due to a problem in a resource DLL. Please determine which resource DLL is causing the issue and report the problem to the resource vendor.

Strange, I thought, since my host was identical as the others, with every patch and updates installed.

I came across this Hotfix from MSFT:

Additional info about the RHS.exe can be found here:

But in my case, there was an error related to NOD Eset Anti-Virus software.
After running Procmon, I found some registry keys that referred to Eset that caused the operation to fail.
After manually removing those entries, my Live Migration started to behave.
In general I must say, that I usually don’t install Anti-Virus on my Hyper-V hosts, since there is so much instability related to Hyper-V and especially when it comes  to Failover Clustering and Live Migration. But this server was recently used as a stand-alone Hyper-V host, and the uninstall procedure of NOD Eset did not remove everything as it should.

Moral: Be careful if you consider Anti-Virus on your Hyper-V hosts.

You will have some interesting problems with Hyper-V if you are using Anti-Virus on your host and do not configure it to exclude certain files and folders related to Hyper-V

Remember to exclude the following in your Anti-Virus software:
      *    VMMS.exe
·         MMS.exe
·         VMWP.exe
·         VMSWP.exe
Also exclude the root directory that contain your virtual machines and configuration files, and the following file extensions:
·         VHD
·         AVHD
·         VSV
·         ISO
·         VFD
·         XML

1 comment:

Anonymous said...

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