Hello,
Today i was confronted to a serious incident, after starting a snapshot merge.
Context : Windows Server 2012, local storage (12+ disk Raid 10), WinServ2012 VM, heavy snapshot to merge (700Go avhdx)
The VM was stopped when i deleted the snapshot.
Problem : after a few minutes, snapshot merging was taking ALL available disk IO (500+ Mo/s to the VM vhdx and avhdx), slowing the whole server to death, and making all running vm unreachable. Took me 30 minutes just to be able to restart vmms.exe, and to finally cancel the snapshot merge. Now it seems the merge process has started again, but with the usual and reasonable disk usage (around 50Mo/s).
Any idea :
- Why it happened ?
- How to stop it fast if it happens again ? (is there a powershell command to stop/pause a snapshot merge ? The UI was not responding)
- How to prevent it ?
Thanks a lot.