TO-Tech Blog Todd Ogasawara’s Tech Blog


Microsoft Virtual Server Saved State Does Not Save State

Patch Tuesday is always a hassle if you have a bunch of virtual machines running in Microsoft Virtual Server 2005 (R2 SP1). I have my VMs set to Save State when VS2005 detects that the host is power off. The majority of the time (say 60 to 80%), the VMs restart and restore from Saved State. However, a couple of times a year, this doesn't happen. I vaguely recalled Microsoft's Virtual PC Guy (Ben Armstrong, Virtual Machines Program Manager) mentioning this in his blog a while back. So, I search his blog and, yep, here's his blog item...

Problems with Virtual Server when shutting down the host

...that leads to Knowledge Base item 888745...

Guest computer state is not saved when you shut down the host computer on Virtual Server 2005

...which recommends dealing with this by making a change in the Registry (a potentially scary process on a server... be very very careful) that changes the WaitToKillServiceTimeout to 90000. FYI: The default value is 20000 on my Windows Server 2003 R2 Enterprise Edition servers.

Unfortunately, this did not fix the problem for me. All my virtual machines set to save state and then restore from saved state after a reboot restarted after rebooting the host to install Patch Tuesday patches. I then made the registry change described in KB888745 and rebooted the host server again. And, again, all my VMs rebooted instead of being restored from Saved State.

FYI: The expected outcome (restore from saved state) worked when I rebooted for the August Patch Tuesday patches (the September Patch Tuesday patches did not require a reboot).

UPDATE: In a Homer Simpson Doh! moment it occurred to me that I need to reboot the test server one more time to see if the registry change actually helps. The WaitToKillServiceTimeout would have still been 20000 and not 90000 in the second reboot described above.