Question concerning managing “Complete System Backup†in Windows V

Discussion in 'Windows Vista Performance' started by RichG, Jul 30, 2007.

  1. RichG

    RichG Guest

    My system is configured as follows…

    OS = Windows Vista Business
    Internal Disk (drive C) = 120Gb
    External Disk (drive H) = 500Gb (USB-connected)

    I ran my first “Complete System backup†of my system on July 11, and chose
    to store the backup files on my external disk (drive H). The backup
    completed successfully, and I verified that the system created a 37Gb VHD
    file along with a few other very small files. I then verified that the
    amount of free space remaining on my external drive was ~37Gb less than I
    previously had free.

    So far, so good…

    I installed two other software applications on my system (Microsoft Visio
    2007 and Microsoft Project 2007), and I launched another complete system
    backup this weekend. The backup completed successfully, and I verified that
    the system created a new 25Gb VHD file along with a few other very small

    I expected to see this new 25Gb VHD file IN ADDITION to the previous 37Gb
    VHD file from the July 11 backup, and was surprised to find that the previous
    37Gb file appears to be MISSING. At least, I cannot find the file in the
    folder where it previously existed.

    I checked the free space on my external H drive, and found that I have ~
    25Gb less free space than I had before. It is as if the 37Gb file is still
    on the drive somewhere, but I cannot find it. When I launch the backup
    program, it states that the last complete backup was run this weekend, and it
    also seems to indicate that a previous backup does exist, but it does not
    list it my name or date.

    I see from the documentation that a complete system backup will run so long
    as enough free space exists, and that it will automatically delete older
    backups (oldest first) as necessary to insure that free space is available.

    I use this external drive to store other information in addition to complete
    system backups, and I need to insure that I always have enough free space to
    handle my needs. My plan was to run a complete system backup whenever my
    system configuration changes significantly, or every month or so – whichever
    comes first. I planned on keeping perhaps 3-4 complete system backups on my
    external drive, and to delete the older backups as necessary.

    NOTE: I am generally aware of volume shadow copy and how it can reduce the
    amount of free space on a volume, but I’m not sure if this is compounding my
    issue or not.


    Can anyone tell me (or does documentation exist that explains) how to manage
    complete system backup files? How does one manage these backups?

    Any assistance is appreciated...
    RichG, Jul 30, 2007
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  2. Hi Rich,

    your assumptions are mostly correct. VSS is turned on at the
    destination where your Complete PC Backups are being saved. At the time you
    created your 2nd backup, block level data representing your 1st backup was
    saved to shadow copy. Therefore the space hit that you are seeing.

    For instance, if you take a 3rd backup, without changing much on your
    system, you'll see that the space usage should grow only by the amount of
    changed blocks between the time you took your 2nd and 3rd backups.

    If you are concerned about the disk space allocation where your backups are
    being saved, I recommend using Disk Cleanup. From there you can delete all
    older shadow copies, but the most recent one. Be aware that this means to
    consequently loose access to older backups.

    Disk Cleanup -> Files from all users on this computer -> Select volume where
    backups are being saved -> More Options -> System Restore and Shadow
    Copies -> Clean up ...

    Eduardo Laureano [MSFT], Jul 31, 2007
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  3. RichG

    RichG Guest


    Thank you very much for the clarification – this makes sense.

    If I understand your reply, my second backup is not a COMPLETE system backup
    by itself…it is only the difference between my original backup and my current

    If so, it would seem to indicate that both of the VHD files (original and
    current) in order to accomplish a complete system restore.

    Is this correct?

    Is there any documentation on the Microsoft WEB site that fully explains
    this from a technical perspective?
    RichG, Jul 31, 2007
  4. The concept is correct, the order is backwards. Once you take your 2nd
    backup, your first backup is now only a set of block level differences
    between the 1st and 2nd. This behavior goes one for subsequent backups.
    Backup n is stored in the VHD, backup n-1 is stored as a set of block level
    differences (between n and n-1) in a shadow copy. And so on ...

    You should typically only have one VHD per volume being backed up. All other
    previous backups are saved in terms of shadow copies.

    On the web you can get information about VSS in general. There's a TechNet
    article coming that will address a lot of the internal behaviors around the
    backup features, but this might take over a month. meanwhile you can see
    some of it on this presentation:


    Eduardo Laureano [MSFT], Aug 1, 2007
  5. RichG

    RichG Guest


    Thank you again for your reply - it is much appreciated.

    Let’s assume that I run the following complete system backups…

    1st – July 1
    2nd – August 1
    3rd – September 1

    As I understand it, I should see only one VHD file, but the other
    information (the delta difference) is stored as volume shadow copy data. If
    I correctly understand your response, this would seem to indicate that a disk
    cleanup should never be run because the erasure of ANY of the shadow copy VHD
    information will prevent a complete system restore.

    Is this correct?

    If my assumption is correct (that disk cleanup cannot be run), I can see a
    disk space management issue as the months go by and my external disk becomes
    full. Again – bear in mind that my external drive is used to store a variety
    of data, not just complete system backup data.

    Before I learned how complete system backup and VSS works, my plan was to
    run a complete system backup once per month (or whenever there was a
    significant system change), and to keep 2-3 months of system backups
    available at any one time. I had planned to manually delete the older
    backups as required to manage my free disk space.

    Can you recommend a best practice methodology here?

    Is there a simple method of managing this space so that it does not keep
    growing as the months go by?
    RichG, Aug 1, 2007
  6. Hi Rick, you illustrated clearly the gist of it. Using disk cleanup does
    delete older backups indeed, but always keep the most recent intact. But a
    lot of users can part with only keeping the most recent backup.

    Recommendations are hard because it depends on usage pattern and amount of
    storage available. But roughly you can take a full system backup every
    couple months and have weekly file backups. If you want to keep one full
    system backup safe (to not be deleted as space becomes needed - let's say
    your backup from when your machine was fully configured), you can store the
    VHD(s) in a separate partition from your usual backup. If you don't take
    further backups in the archive partitions, your backup will never "age out".

    This posting is provided "AS IS" with no warranties, and confers no rights.

    Eduardo Laureano [MSFT], Aug 2, 2007
  7. RichG

    BillH Guest

    Excuse me for jumping in here, but I've been using Vista Ultimate's Backup
    and Restore Center to back up my laptop to an external 500GB drive weekly
    since April. I am now out of space on the external drive and I can't seem to
    find any way of eliminating the redundancy of the file backups. I did the
    recommended disk image backup and then set it up to backup files. I never
    dreamed I'd run out of space so soon. Is there any way to trim down the file
    backups to just the latest version or two? I tried the disk cleanup program,
    but it said nothing about backup versions that I could see on either the C:
    drive or the G: drive where the backups are.

    BillH, Aug 7, 2007
  8. RichG

    RichG Guest


    This is exactly the scenario I am hoping to avoid. I appreciate the
    information Eduardo has provided thus far, but I still do not see an easy way
    to manage this space in an efficient manner. I hate to say this, but I am
    now considering acquiring a 3rd party product such as Norton's Save & Restore
    given the lack of admin & maintenance tools for Vista's Complete PC Backup &
    file-based backup stragegy.

    Eduardo - I look forward to your reply to Bill's query...

    RichG, Aug 7, 2007
  9. RichG

    RichG Guest

    I was just browsing the news group for other postings, and I saw the
    following posting...

    Hi David,

    Vista won't recognize a USB drive until the OS is fully loaded, it has (to
    my knowledge) no provisions for loading from or to one during any point of
    setup other than grabbing a driver for a RAID configuration or SATA drive.
    Which, non coincidentally, may be the issue with the SATA drive. It may
    require a manufacturer's driver to access it fully.

    You mentioned you created these as network shares, were they attached
    locally and mounted as such? or were they attached elsewhere on the network
    and mapped?


    Rick Rogers reply seems to indicate that a complete PC restore is not
    possible from a USB-connected hard disk. If true, then my current backup
    strategy is essentially useless (from a complete PC restore standpoint.

    I did mention in my initial posting that my external 500Gb disk is USB

    Can you please confirm - is it true that a Complete PC Restore is not
    possible from a USB-connected external disk?
    RichG, Aug 7, 2007
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