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DPM 2010 not filling tapes on a Quantum Superloader3 with LTO3 drive RRS feed

  • Question

  • Hi all,

    We have a Quantum Superloader 3 library (drivers are QsmcX64.sys and QmCox64.dll, both v2.5.1.0) with a Quantum LTO-3 drive (firmware D21T, drivers are QLTOx64.sys and LT154x64.dll, both version 3.4.0.0). DPM2010 is v3.0.7706.0.

    To begin with, we had many problems with LT tape jobs like this one:

    ==================

    The back up to tape job failed for the following reason: (ID: 3311)

    DPM encountered a critical error while performing an I/O operation on the tape Server Protection Group-LT-1Weeks-Copy0-00000069 (MSD981L3) (Barcode - MSD981L3) in Drive Quantum LTO 3 Tape Drive. (ID: 30101)

    ==================

    Setting the BufferQueueSize to 2 seems to have made these errors go away (values of 1 and 3 didn't help - only 2 made a difference).

    However, we now have the problem that only a tiny amount of data (tens of gigabytes at the utmost; usually a lot less) is getting written to each tape before DPM swaps in a new one. We already have the TapeSize registry key set to 400000 (decimal), which I hope is an appropriate value for an LTO3 tape. There are no apparent hardware or SCSI errors in the Windows event logs, or on the drive itself.

    Why is DPM writing so little data to each tape? We have just one Protection Group, using short-term disk and long-term tape backup. Co-location on tape is enabled, and I would expect this group to consume around 600GB of tape in total (i.e., one or two tapes, depending on compression).

    Any ideas why DPM is swapping tapes so frequently?

    many thanks,
    alec

    Monday, June 27, 2011 12:51 PM

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