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Client backup space much smaller than data space on client machines RRS feed

  • Question

  • My first backups succeeded last night.  However the space they took up on the backup machine's drive (201GB) was much smaller than the space taken up on the client machines (646GB).  Does WHS 2011 perform some form of compression?  If compression is done is this a user configurable setting?
    Wednesday, July 6, 2011 5:56 PM

All replies

  • "However the space they took up on the backup machine's drive (201GB) was much smaller than the space taken up on the client machines (646GB)"

    Does that imply you have more than one client? If so, any duplication of files (e.g. The Operating System) on different PCs are only copied once.

     


    Phil P.S. If you find my comment helpful or if it answers your question, please mark it as such.
    Wednesday, July 6, 2011 6:04 PM
  • There are two clients so far.  The operating system wouldn't account for the difference.  The second system is our data server.  It has tons of SQL Server backup files that are all uniquely named.  Is compression happening?
    Wednesday, July 6, 2011 7:10 PM
  • There's no intentional data compression in the sense you mean. That said, SQL Server backups are full of redundant data, and that may result in some level of effective compression because of the way data is stored. When data is backed up, only one copy of a given cluster of data is ever stored, no matter how many times a cluster with that exact data is actually found.
    I'm not on the WHS team, I just post a lot. :)
    Wednesday, July 6, 2011 7:46 PM
  • Would you think it normal or unusual to have 646GB of data back up in 201GB given that the only things the same on the two systems is the OS.  Is there a way that I can test that the backups have done there job (without restoring data)?
    Wednesday, July 6, 2011 7:53 PM
  • Would you think it normal or unusual to have 646GB of data back up in 201GB given that the only things the same on the two systems is the OS.  Is there a way that I can test that the backups have done there job (without restoring data)?
    Speaking as an IT pro, a disaster recovery plan that hasn't been through an end to end test may as well not exist, because you have no idea what you may not have anticipated. That includes testing a backup/restore cycle. There's no reason to restore to the disk currently in the SQL machine, however; you can always restore to some other disk (same size or larger), test to make sure everything is good, and switch back.
    I'm not on the WHS team, I just post a lot. :)
    Wednesday, July 6, 2011 8:41 PM
  • I think the only thing that will show is that whatever data was backed up can be restored.  It's not going to show that all data that should have been backed up, was backed up.  My concern is the 3:1 discrepancy between that amount of data scheduled to be backed up and the amount that was actually backed up.  As far as I can tell there is no validation capability on the server.

    Given all of the other issues I have had with the product (server reinstalled 4 times, clients took over a week to install until I found a posting on another forum about registry hangovers from pervious client installs, remote backup won't install, and now this data discrepancy), my comfort level is not very high.

    In general I have been very high on Microsoft software and the support and general reliability.  WHS 2011 is another type of product all together.  It's almost as if Microsft through it out to the world as a utility.  Clearly others in the market think this or there would be antivirus capabilities already.  In this day and age it can't be that difficult to build a reliable and easy to install backup product that will work across a network.  Backup is really all I bought this product for.  I could care less about what else it can and can't do.



    Wednesday, July 6, 2011 10:15 PM
  • Situation got worse when I added two more clients with a combined total of 152GB of used storage.  Only 41GB was added to the backup storage, yet all backups read as successful.  Now I have 242GB in the backup storage for four clients that have a total of 808GB of used storage.
    Thursday, July 7, 2011 9:48 PM
  • This is still entirely possible; it depends heavily on how much duplicate data there actually is between the various computers being backed up. You can learn a bit more by reading the Home Computer Backup and Restore Technical Brief (note that it's for the previous version of the product, but the backup engine hasn't changed much) which will explain a bit more about how backups are stored.

    That said, however, the only way to be certain that backup/restore works as you need it to, and to work out what possible issues you might encounter, is to actually restore a computer.


    I'm not on the WHS team, I just post a lot. :)
    Friday, July 8, 2011 2:04 AM
  • Thanks Ken.  This is good information.  I wish we had this level of information for WHS 2011.
    Friday, July 8, 2011 7:44 PM
  • Thanks Ken.  This is good information.  I wish we had this level of information for WHS 2011.
    I've asked the team about this. The answer I've generally gotten is "<mumble><mumble>on our plates<mumble><mumble>soonish<mumble><mumble>". So someday. To give an idea of what kind of time frame we're really talking about, though, the last set of technical briefs took something like a year from product release. So don't hold your breath.
    I'm not on the WHS team, I just post a lot. :)
    Friday, July 8, 2011 8:25 PM