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Restoring computer image to a smaller hard disk? RRS feed

  • Question

  • Just a simple question.

    Let's say you backup a computer through WHS. One day the computer's hard drive dies and you want to pop in another hard drive, then restore the latest image from WHS. From my understanding, you cannot restore a computer image through WHS onto a hard drive that is smaller than the original cloned drive.

    I am just wondering if perhaps there may be a way around this, or would there be any plans in the future to allow this to happen?
    Saturday, April 18, 2009 10:56 PM

Answers

  • Hi,
    sometimes it may work, AFAIK this depends from the postion of the last data on the disk. But you are right, this is a limitation of the restore process by Windows Home Server, which could have been done better even with always cheaper and larger disks available.
    All potential workarounds would involve a large enough volume as well. This you could shrink after restore (using diskpart within the cmd prompt in Vistas Setup DVD repair environment, Disk Management console in Vista or a 3rd party tool) and then backup that smaller volume again.
    Feel free to register at Microsoft Connect and vote for one of the proposals for allowing restore to a smaller volume as long, as the data would fit.
    Best greetings from Germany
    Olaf
    Sunday, April 19, 2009 12:01 AM
    Moderator
  • Unfortunately, in my experience, the position of the data on the backup disk makes no difference.  The restore program does not seem to be that sophisticated.  The partition you are restoring to, must be at least as large as the back up partition, regardless of the actual amount of data on the back up partition.
    Actually, it does matter, but not in the way that one would expect, and your rule of thumb is likely to apply in most cases. When you write a file to a disk that's formatted with NTFS, several areas of the disk get written to. Tools that move files to the beginning of the disk will generally only move files, not the additional data (Master File Table and backup, alternate streams, etc.) so unless a disk is brand new, you will generally not be able to restore an image to anything smaller than the original disk. Also, even if a disk is brand new and only has a few GB of data on it (say a fresh OS installation) you may still need a disk that's half or more the original disk's size because of the way that NTFS lays data down on the disk.

    I'm not on the WHS team, I just post a lot. :)
    Sunday, April 19, 2009 1:15 PM
    Moderator

All replies

  • Hi,
    sometimes it may work, AFAIK this depends from the postion of the last data on the disk. But you are right, this is a limitation of the restore process by Windows Home Server, which could have been done better even with always cheaper and larger disks available.
    All potential workarounds would involve a large enough volume as well. This you could shrink after restore (using diskpart within the cmd prompt in Vistas Setup DVD repair environment, Disk Management console in Vista or a 3rd party tool) and then backup that smaller volume again.
    Feel free to register at Microsoft Connect and vote for one of the proposals for allowing restore to a smaller volume as long, as the data would fit.
    Best greetings from Germany
    Olaf
    Sunday, April 19, 2009 12:01 AM
    Moderator
  • Hi,
    sometimes it may work, AFAIK this depends from the postion of the last data on the disk. But you are right, this is a limitation of the restore process by Windows Home Server, which could have been done better even with always cheaper and larger disks available.
    All potential workarounds would involve a large enough volume as well. This you could shrink after restore (using diskpart within the cmd prompt in Vistas Setup DVD repair environment, Disk Management console in Vista or a 3rd party tool) and then backup that smaller volume again.
    Feel free to register at Microsoft Connect and vote for one of the proposals for allowing restore to a smaller volume as long, as the data would fit.
    Best greetings from Germany
    Olaf

    Unfortunately, in my experience, the position of the data on the backup disk makes no difference.  The restore program does not seem to be that sophisticated.  The partition you are restoring to, must be at least as large as the back up partition, regardless of the actual amount of data on the back up partition.

    I had a netbook with a 320GB HDD, and wanted to replace it with the original 160GB HDD before selling the netbook.  I had only about 30 GB of files on the hard disk, and used Perfect Disk to move all files to the beginning of the drive.  I had almost 290 GB of continuous free space at the end of the disk. I like keeping my disks defragged and consolidated this way - perhaps a bit of OCD behaviour - LOL.

    I then performed a backup, replaced the 320GB HDD with the 160GB, and attempted to restore the drive information.  I was unable to do so - the WHS restore program would still not let me restore 30GB of data from a 320 GB volume to a 160 GB volume.

    I then placed the 320GB drive back into the netbook, as was able to shrink the single parition all the way down to 32GB using Vista Disk Tools.  After that I performed another backup and was then able to restore the data to the 160GB hard drive.
    • Edited by dpkform Sunday, April 19, 2009 1:59 AM corrected wording
    Sunday, April 19, 2009 1:54 AM
  • Unfortunately, in my experience, the position of the data on the backup disk makes no difference.  The restore program does not seem to be that sophisticated.  The partition you are restoring to, must be at least as large as the back up partition, regardless of the actual amount of data on the back up partition.
    Actually, it does matter, but not in the way that one would expect, and your rule of thumb is likely to apply in most cases. When you write a file to a disk that's formatted with NTFS, several areas of the disk get written to. Tools that move files to the beginning of the disk will generally only move files, not the additional data (Master File Table and backup, alternate streams, etc.) so unless a disk is brand new, you will generally not be able to restore an image to anything smaller than the original disk. Also, even if a disk is brand new and only has a few GB of data on it (say a fresh OS installation) you may still need a disk that's half or more the original disk's size because of the way that NTFS lays data down on the disk.

    I'm not on the WHS team, I just post a lot. :)
    Sunday, April 19, 2009 1:15 PM
    Moderator
  • Actually, it does matter, but not in the way that one would expect, and your rule of thumb is likely to apply in most cases. When you write a file to a disk that's formatted with NTFS, several areas of the disk get written to. Tools that move files to the beginning of the disk will generally only move files, not the additional data (Master File Table and backup, alternate streams, etc.) so unless a disk is brand new, you will generally not be able to restore an image to anything smaller than the original disk. Also, even if a disk is brand new and only has a few GB of data on it (say a fresh OS installation) you may still need a disk that's half or more the original disk's size because of the way that NTFS lays data down on the disk.

    Yes - this is something I learned with PerfectDisk - it categorizes those types of files.  Somehow, by fiddling with the settings and doing several passes of offline and online defrags, I managed to arrange the continuous free space portion at the end of the disk, to be almost equal to the total free space remaining.

    Lesson learned for me - I now create minimal size partitions on a disk, leaving the rest as undefined. It is much easier to expand the partition when needed than to try and shrink it in the future.  Also a natural way to limit defragging, and to ensure the data transfer performance, by keeping the data as far to the outside of the disk as possible.
    Monday, April 20, 2009 7:14 AM