Merge of VHD with AVHD and no Hard drive Space


  • Hi all, I have a curly one.

    I have no room on my hard drive (Windows server 2008) which host my two hyper v servers.

    The previuos It Guy made a snapshot 6 months ago so I have a avhd thats about 200GB but I only have 100 GB space.

    My VHD was 10GB and the avhd is 200GB

    I started the merge and got scared and cancelled it as My hard drive space was going down rapidly. I know have a vhd at 70GB (as I did merge with parent) and a avhd that is still 200GB.

    My 3 questions are :

    1)whats the best process to merge these files into one VHD

    2)Can I cut and paste a VHD  and the virtual server will start up again eg:  (If I stop my other server (DC), move the vhd toa  external drive, merge the vhd and avhd and then once this is done move back the dc vhd to the server)

    3)Can I merge the avhd by moving it to a USB drive and then nerging to parent with the edit disk , merge facilty.

    Thanks Guys



    Tuesday, November 30, 2010 11:36 AM

All replies

  • Hi Phil.

    I have two suggestions to you here:

    1) Merge the snapshots with Hyper-V 


    1. Shut down all VMs

    2. Move (copy-delete) all VM folders to another HD (can also be USB) except the one to be merged

    3. Delete the snapshots of the specific VM

    4. Move the VM to another HD

    5. Copy the next VM back from another HD.

    6. Repeat step 3-6 until all VMs are shrunk


    2) Check out Brian`s post for how you can manually merge the avhd files to vhd:


    Kristian (Virtualization and some coffee: )
    Tuesday, November 30, 2010 12:11 PM
  • HI Kristian and Thanks,

    You have clarified that it can be simply moved on to a usb drive. Effectively CUT AND PASTE with out any affects (well move copy then delete) THANKS

    In regards to the snapshot, there are none in hyper v manager but the avhd exists. I shut downand waited 1 day and no merge happened. That is when I went to do the manuial merge and canceled it.

    The only other question is I might not have enough room on my hard drive even if I move all the vhd's and avhds except the one to merge.

    Can I move (Cut) the avhd to a usb drive and then merge it with the vhd on the local server while it being on the usb drive.Then delete it from the usb drive as it is merged.

    Thanks again


    Tuesday, November 30, 2010 8:39 PM
  • Hi Phil.

    Please check similar threads: ,

    Also, if you are running 2008 R2, you are able to create a new snapshot, export the snapshot, delete your VM, and import the snapshot as a new VM again.



    Kristian (Virtualization and some coffee: )
    Tuesday, November 30, 2010 10:02 PM
  • OK Thanks.

    Sorry to be forward, but can i move the vhd and out it back with no problems. I would really like to know


    Tuesday, November 30, 2010 10:10 PM
  • Phil: In general, you can move your vm, as long as you specify the location of the configuration file and .vhd. But I do not know the current state of your VM, since you are saying that you have deleted the snapshots, no merging has taken place, and the .avhd files remains

    Please try to power off your VM once again, and see in the 'Status' bar in Hyper-v Manager, if the merge process starts. (It can take up til 3 minutes before the merge starts).


    Kristian (Virtualization and some coffee: )
    Tuesday, November 30, 2010 10:33 PM
  • Hi Kristian and Thanks again, I really appreciate your advice

    I didnt delete the snapshots , there were none when I got there but a AVHD file exists and was the only file being modified..

    I already tried 3 times now and to no avail :(

    I have started to merge it but was running out of sapce so stopped it. the parent VHD was 10GB and is now 70GB. The avhd is 200GB.


    All I want to do is move one servers vhd to a usb drive, merge the other vhd and avhd, then move the other server vhd back and strat the server again.

    By the looks of it, Its all good.

    This weekend I will try it and do a export of both machines, copy them manually and do a server backup within the servers first


    Cant have to much backup





    Tuesday, November 30, 2010 11:08 PM
  • Hi All,


    As I am doing the merge tomorrow.

    Does anybody want to tell me that this could cuase issues:

    1)Turn off a server in hyper v

    2)through windows explorer move the vhd (copy paste delete) to a usb drive or 2 for extra protection.

    3)Do the merge on a totally differnt hyper v server than the one I moved. (The other server was moved for disk space only

    4)Put the untouched VHD back and start all servers

    Thanks for your input


    Thursday, December 02, 2010 12:05 PM
  • Hi Phil. Any update on this?
    Kristian (Virtualization and some coffee: )
    Tuesday, December 28, 2010 8:50 AM