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DPM 2010 Tape Backup only using half tape capacity RRS feed

  • Question

  • Hello,

    I am trying to run a weekly tape backup for the following scenario

    1 protection group backing up 2 HyperV servers.

    Server A replica volume is 754gb and Server B replica volume is 813gb.  I am using a standalone LTO4 drive with 1600gb tapes.  When running the tape backup the backup runs to around 550-600gb capacity on the tape and then requests another tape, this then runs to 500gb as well and requests another tape and therefore a backup of around 1.5tb is requiring 3 x 1600gb tapes? I have tried the backup with co-locating enabled and disabled with the same results for both options.

    Is there anyway to force the tape to run to full capacity?

     

     


    • Edited by Babsy2000 Monday, January 16, 2012 3:13 PM
    Monday, January 16, 2012 11:16 AM

Answers

All replies

  • Hello,

     

    you are not alone :-( . I have the same thing. It seems to be a bug in DPM 2010. Did you change the tape device anytime? This is my problem.

     

    Yours is that the LDT4 Tape have 800GB native, 1600GB compressed. If your PG can not be compressed good (2:1) than it schoud at least write ~800GB to one Tape, not 500GB

    Monday, January 16, 2012 3:15 PM
  • This is a fresh install od DPM 2010 with an internal tape drive, the drive hasn't been changed.  The tape backup has never worked to full capacity

    So no solution...??

    Monday, January 16, 2012 3:24 PM
  • Hello,

     

    you are not alone :-( . I have the same thing. It seems to be a bug in DPM 2010. Did you change the tape device anytime? This is my problem.

     

    Yours is that the LDT4 Tape have 800GB native, 1600GB compressed. If your PG can not be compressed good (2:1) than it schoud at least write ~800GB to one Tape, not 500GB


    http://social.technet.microsoft.com/Forums/en-US/dpmtapebackuprecovery/thread/e718e8e6-c0d6-496e-9407-ea1ccf51bb98#56da37d0-7cea-461f-9d0a-f54f8418ffcb

    you can try this link to check if you taoe device writes the tapes correctly

    Monday, January 16, 2012 3:28 PM
  • Hi Babsy,

    Just to check - is tape compression enabled on the PG in the "Select library and tape details section"? It's off by default.

    The 2:1 compression ratio is optimal and is probably not achievable in the real world (I've never seen it regardless of backup product used). The best I've ever got with our data set is around 1.5:1

    Monday, January 16, 2012 4:35 PM
  • Hi, yes I have tape compression enabled.  Just thought 500gb on a 1600gb tape is pretty poor performance
    Monday, January 16, 2012 4:49 PM