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VHD Snapshot Size RRS feed

  • Question

  • Hi,

    I have got a question about VHD snapshots on the Hyper V cluster. System Centre backs up everyday and I compared the size from January 2014 and up to now. it has gone up. It used to Backup 565GB and now it is showing me 609 GB. I have deleted removed big chunks of files from the server to an external drive but it is still backing up over 600GB. Any reason for it to do so?

    Thanks

    Monday, May 12, 2014 8:17 AM

All replies

  • Hi,

    Need more information. Are you performing disk to tape (D2T) or Disk to Disk to tape (D2D2T) hyper-v host level backups ?

    Where are you seeing the total backup size increase ?  If you removed data from inside a guest's VHD - did you Compact the .vhd to reduce it's size ? 


    Please remember to click “Mark as Answer” on the post that helps you, and to click “Unmark as Answer” if a marked post does not actually answer your question. This can be beneficial to other community members reading the thread. Regards, Mike J. [MSFT] This posting is provided "AS IS" with no warranties, and confers no rights.

    Monday, May 12, 2014 6:14 PM
    Moderator
  • Hi, I am performing short term to disk then from disk 2 tape, and the short term only copies changes but the long term backs up the whole VHD and that is where the size is growing. I do not need to reduce or compact the VHD as it already had 600 Gb. I have not increased the drive. It is an unusual behaviour to increment automatically.
    Monday, May 12, 2014 8:43 PM
  • Hi,

    So am I to understand that the .VHD's are all "Fixed Size" ?  If not, I'm not understanding why after removing files from the VM that a compact would not help reduce the size of the VHD file.  Once it's reduced on the protected server, it will be reduced on the DPM replica and the tape backups will be back to a smaller size.


    Please remember to click “Mark as Answer” on the post that helps you, and to click “Unmark as Answer” if a marked post does not actually answer your question. This can be beneficial to other community members reading the thread. Regards, Mike J. [MSFT] This posting is provided "AS IS" with no warranties, and confers no rights.

    Monday, May 12, 2014 9:12 PM
    Moderator
  • Hi Mike,

    I have not tried to compact it as VM is running on the Hyper V cluster. Whole VM size is 650GB and it seems to be going up on the tape. it is not only on one VM but all 7 VMs.

    Tuesday, May 13, 2014 8:33 AM
  • Hi,

    It is expected that the whole VM size is written to tape - it seems that compacting is the right thing to try to see if the .vhd files can be shrunk.


    Please remember to click “Mark as Answer” on the post that helps you, and to click “Unmark as Answer” if a marked post does not actually answer your question. This can be beneficial to other community members reading the thread. Regards, Mike J. [MSFT] This posting is provided "AS IS" with no warranties, and confers no rights.

    Tuesday, May 13, 2014 2:54 PM
    Moderator
  • I can not find compact option. where do you think I should look for it?

    Thanks,

    Wednesday, May 14, 2014 7:33 AM
  • Hi,

    Use the "edit disk" wizard and browse to select the .VHD you want to compact, then select the compact option.


    Please remember to click “Mark as Answer” on the post that helps you, and to click “Unmark as Answer” if a marked post does not actually answer your question. This can be beneficial to other community members reading the thread. Regards, Mike J. [MSFT] This posting is provided "AS IS" with no warranties, and confers no rights.

    Wednesday, May 14, 2014 3:01 PM
    Moderator
  • Hey Mike,

    I have tried the Compact option and it has not made any impact to tape backup size. I can not think of anything.

    Friday, May 16, 2014 2:55 PM
  • Hi,

    Can you tell if the .vhd size was reduced on the protected server - if it did not reduce it, then it will not reduced on DPM replica so the tape backup size will remain the same.


    Please remember to click “Mark as Answer” on the post that helps you, and to click “Unmark as Answer” if a marked post does not actually answer your question. This can be beneficial to other community members reading the thread. Regards, Mike J. [MSFT] This posting is provided "AS IS" with no warranties, and confers no rights.

    Friday, May 16, 2014 6:16 PM
    Moderator
  • It is 600 GB dynamic expanding and it has 350 GB data. It backs up full BHD and it is incrementing. I have no idea where is the extra size coming from? It is like a plant growing within DPM without the water and I don't think it is possible.
    Friday, May 16, 2014 7:51 PM
  • Hi,

    If you restore the VM to a network location from the last disk based recovery point that is also on tape, what is the total size of the recovered files ?  If you then restore the same recovery point from the tape based recovery point - is the size the same ?


    Please remember to click “Mark as Answer” on the post that helps you, and to click “Unmark as Answer” if a marked post does not actually answer your question. This can be beneficial to other community members reading the thread. Regards, Mike J. [MSFT] This posting is provided "AS IS" with no warranties, and confers no rights.

    Friday, May 16, 2014 9:56 PM
    Moderator
  • Yes the size is. Same 600 gb.
    Monday, May 19, 2014 6:53 PM
  • HI,

    OK - I really don't see any problem, The DPM disk based recovery point VM size is 600GB and so is the tape based recovery point.  So I guess the goal should be to still see if you can get the .VHD size down.  I suggest you try defragging the volumes in the VM then try compacting again so the .VHD size is reduced.  Once it's reduced on the protected server, it will be reduced on the DPM server and tape backups will also be reduced.

    Compacting a Dynamically Expanding virtual hard disk in Windows Server 2012 


    Please remember to click “Mark as Answer” on the post that helps you, and to click “Unmark as Answer” if a marked post does not actually answer your question. This can be beneficial to other community members reading the thread. Regards, Mike J. [MSFT] This posting is provided "AS IS" with no warranties, and confers no rights.

    Monday, May 19, 2014 7:18 PM
    Moderator