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DPM 2007 - Tape drive issues (backing data from protection group over 3 tapes) RRS feed

  • Question

  • Hi

    We have been using DPM2007 for the past few years, and i am wondering if anybody else is having the same problem.

    We currenty backup every thing to disk first then do nightly or weekly tape jobs.

    We currently use an LTO4 tape drive (1.2TB free on each disk), one of our protection groups is approx (800gb) yet DPM is spanning this tape backup over three tapes, when it wouldactually fit on 1 tape, how can i fix this.

    I have enable colocating but it is not an option as i need to get the tapes offsite everyday, anybody have any ideas.

    ALso is there any tape inventory report that i can run, as i am constantly placing media that is full into the drive and dpm will not over write it or erase it.

     

    Friday, June 18, 2010 11:54 AM

Answers

  • Hello,

     

    It sounds like the tape drive is reporting I/O errors before reaching end of tape. DPM reads the following reg key

     [HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Microsoft Data Protection Manager\Agent]
    "TapeSize"=dword:00030000

    If driver sends an IO_DEVICE_ERROR and amount of data written by DPM is more than TapeSize value (in MBs), DPM will auto convert IO_DEVICE_ERROR to END_OF_TAPE_REACHED and span to next media without any issues.


    Default behavior is for DPM to treat any I/O error after more than 30GB is written to tape as an “end of media” and will cause a new tape to be used.  If backups then start failing due to I/O errrors then you can enable this registry key:

    [HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Microsoft Data Protection Manager\Agent]
    "BufferQueueSize"=dword:00000002

    Without the registry key the default buffer queue size is 10. The reg. key overrides the value and sets it to 2.

     

    Also, you can run a tape Management report and select next 4 weeks and it will tell you when tapes are DUE back or overdue so they can be re-used for future backups. 


    Regards, Mike J [MSFT] This posting is provided "AS IS" with no warranties, and confers no rights.
    Friday, June 18, 2010 3:23 PM
    Moderator

All replies

  • If you have enabled colocating (not sure from your post), other protection jobs may be storing data on the tape.  Also, LT04 is 800GB native so you need to turn on compression to achive more.  I dont think there is an inventory report for tapes.  I use a spreasdsheet to track, but if you are ready to reuse a tape that has not yet expired, it means your need to shorten expiration date in the protection group.
    Friday, June 18, 2010 2:20 PM
  • Thanks for the reply

     

    I have enabled colocating and the data is being compressed so it should take at least 1tb.

     

    I am also using a spreadsheet, but this seems to be a really poor solution

    Friday, June 18, 2010 2:48 PM
  • Hello,

     

    It sounds like the tape drive is reporting I/O errors before reaching end of tape. DPM reads the following reg key

     [HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Microsoft Data Protection Manager\Agent]
    "TapeSize"=dword:00030000

    If driver sends an IO_DEVICE_ERROR and amount of data written by DPM is more than TapeSize value (in MBs), DPM will auto convert IO_DEVICE_ERROR to END_OF_TAPE_REACHED and span to next media without any issues.


    Default behavior is for DPM to treat any I/O error after more than 30GB is written to tape as an “end of media” and will cause a new tape to be used.  If backups then start failing due to I/O errrors then you can enable this registry key:

    [HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Microsoft Data Protection Manager\Agent]
    "BufferQueueSize"=dword:00000002

    Without the registry key the default buffer queue size is 10. The reg. key overrides the value and sets it to 2.

     

    Also, you can run a tape Management report and select next 4 weeks and it will tell you when tapes are DUE back or overdue so they can be re-used for future backups. 


    Regards, Mike J [MSFT] This posting is provided "AS IS" with no warranties, and confers no rights.
    Friday, June 18, 2010 3:23 PM
    Moderator
  • thanks for the replies - i will try the registry fix and let you know how it goes
    Wednesday, June 23, 2010 1:47 PM