Will Merge-VHD function physically delete files from disk?

Mar 26, 2012 at 1:43 PM


Does this function frees disk space, or only points Hyper-V do not use snapshots?

Mar 29, 2012 at 12:01 AM

Yes, it will free disk space, but not immediately.  The merge function will merge the contents of the avhd files with the vhd file, but the actual merge does not take effect until the VM is turned off.  At that time, the disk space is freed up.

Mar 29, 2012 at 9:09 AM


Thank for Your response!

But is there a function than deletes unrequired snapshot files? The idea is to make script that deletes old snapshots and creates new in sheduler. But that increases size of  *.avhd files on disk. And It would be perfect if we do it without turn off or save state..

Apr 2, 2012 at 5:18 PM

The architecture of the snapshot is that it is merged upon shutdown.  That can't be changed in the current version.  I think it is changing in Windows 8.

It almost sounds like you are using snapshots for backup purposes.  Microsoft recommends against that practice.  Snapshots are great for things like development environments, but in a production environment, you can create backups across applications that really aren't in sync with one another.

Apr 2, 2012 at 5:45 PM


Thank You very much for Your answers, now we understand situation clearly. 

Yes You are right, we have backup mechanism now, but I wanted to make few snapshots at same time, becouse we have problems with simultaneously backup of mail server and DC(mail server vhd size is near 600 GB). So snapshots that could dissapear would be very cool for us, unfortunately not in this version.

Ok TimCerl, Thank You twice for Your response! :)