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sql backup size requirements on the protected server RRS feed

  • Question

  • server 2003 with sql 2005, backed up by dpm 2010.

    How much free space is needed on the protected server? 

    When a sql full backup runs, how much space does the snapshot take in comparison to the db size?

    Just to be clear, I'm not trying to calculate how much space I need on the DPM server, I'm worried about the SQL server.

    Thanks.



    Friday, July 13, 2012 7:58 PM

All replies

  • Hi,

    The initial snapshot size I believe is either 300mb or 600mb.  Depending on the SQL DB Write activity after the snapshot is created will determine if we need to use more than that before the backup finishes and the snapshot deleted.  If you are doing incremental sync also, then the DPM_SQL_PROTECT directory gets created where the .ldf file of the backed up database is present and it’s not possible to customize it.

    Every successful incremental should delete the older copy of the .ldf files, so the drive should not get progressively full and involve any admin intervention.

    You should be able to make that folder a mountpoint and use a separate drive.  Just remove all subfolders so the directory is empty to make the mountpoint and they will get recreated on the target mounted volume.

     

    Use MKLINK utility to create a link called DPM_SQL_PROTECT which points to a directory on another drive.


    C:\Windows\system32>mklink
    Creates a symbolic link.

    MKLINK [[/D] | [/H] | [/J]] Link Target

            /D      Creates a directory symbolic link.  Default is a file
                    symbolic link.
            /H      Creates a hard link instead of a symbolic link.
            /J      Creates a Directory Junction.
            Link    specifies the new symbolic link name.
            Target  specifies the path (relative or absolute) that the new link
                    refers to.

     
       mklink /J DPM_SQL_PROTECT E:\DPMLOGS

     


    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, July 13, 2012 9:58 PM
    Moderator
  • Mike,

    When doing an express full backup, how much disk space on the SQL server is used in comparison to the size of the db?  For example, if the db's mdf is 75GB, will the snapshot also be 75GB?

    Thanks



    • Edited by beneb Tuesday, July 17, 2012 3:39 PM
    Tuesday, July 17, 2012 3:39 PM
  • Hi,

    No - as stated earlier, the snapshot size depends on the amount of changed SQL data while the snapshot is active.  VSS does copy-on-write to maintain the snapshot, so the more SQL writes that occur the more space that is needed to maintain the snapshot.   The snapshot is deleted once DPM copies what it needs from the snapshot.


    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, July 17, 2012 4:36 PM
    Moderator