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Snapshot of azure vhd storage

    Question

  • I have 100 gb vhd created in azure storage.

    The disk has only 5 GB of data.

    If I take snapshot of my storage then it will take full 100GB space every snapshot or only 5 GB  and how.

    Thanks,

    Subodh


    Thanks, Subodh

    Tuesday, August 4, 2015 7:49 AM

Answers

  • neither. the snapshot will be the size of the changes since it was taken.

    if you take a snapshot of this vhd and then copy a 1 GB file to it, the snapshot will be 1 GB

    Tuesday, August 4, 2015 7:51 AM
  • Benny is right, if the snapshot is exactly the same as the original vhd (page blob), no extra space is needed for this newly created snapshot as it shares the same data with the original vhd. As time goes by, the original vhd has more and more different data with the snapshot, so new space will be created to store the new data of the original vhd, but old data will be still reserved for the snapshot.

    In short, the extra space cost of a snapshot is approximately capacity of the delta data between original vhd and snapshot.

    Friday, August 7, 2015 2:14 AM

All replies

  • neither. the snapshot will be the size of the changes since it was taken.

    if you take a snapshot of this vhd and then copy a 1 GB file to it, the snapshot will be 1 GB

    Tuesday, August 4, 2015 7:51 AM
  • Ok. So  I have 100GB VHD which is mounted on VM and it is bit locker encrypted.

    If login to VM the actual data will be 5 GB.

    Now I take snapshot.

    I add 1 GB to it.

    Then the snap shot will be created for 1 GB ?


    Thanks, Subodh

    Tuesday, August 4, 2015 11:37 AM
  • exactly
    Wednesday, August 5, 2015 4:43 AM
  • Benny is right, if the snapshot is exactly the same as the original vhd (page blob), no extra space is needed for this newly created snapshot as it shares the same data with the original vhd. As time goes by, the original vhd has more and more different data with the snapshot, so new space will be created to store the new data of the original vhd, but old data will be still reserved for the snapshot.

    In short, the extra space cost of a snapshot is approximately capacity of the delta data between original vhd and snapshot.

    Friday, August 7, 2015 2:14 AM