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DPM Unnecessarily Using Multiple Tapes RRS feed

  • Question

  • Hello,

    I've been noticing that DPM 2012 R2 has sometimes been splitting a nightly backup over multiple tapes (even though it can fit on a single tape). We are using LTO-6 tapes with an HP StorageWorks MSL2024 G3 library. Normally, the backup should complete and all fit on the one tape. But as I said, sometimes it will use two or three tapes for the same protection group backup, and put ~100 GB on one tape, then decide that it needs another. This is obviously very wasteful.

    Is there some was that we can tell exactly what's going on here and prevent it?

    Thank you

    Tuesday, July 14, 2015 6:31 AM

All replies

  • Hi,

    There are a number of factors that can contribute to that behavior.  You will need to troubleshoot by process of elimination.

    1) Check your tape co-location settings and make sure each Protection Group (PG) belongs to a co-location PGSet.  If a PG does not belong to a PGSet, the tapes will be marked offsite ready immediately following the backup completion.  This will force using a new tape for subsequent backups.

    2) Check the expiry tolerance and write period in each co-location PGSet. For DPM to protect a data source, it must first "sync" that data source with DPM's own copy of that data source on disk.  DPM's LT tape backups are always disk-to-disk-to-tape.  When a tape backup of a data source occurs, DPM uses the latest sync'ed copy of the data source.  If the latest copy of one data source is older enough than another data source, then colocation is prevented because the Expiry Tolerance prevents the two data sources from being eligible to be put on the same tape. 

    3) Check for IO errors by searching the DPMRA*.errlog files for error code 0x8007045D. If you find any, see the below BLOG to help eliminate them.

    BLOG-things-you-can-do-to-help-data-protection-manager-utilize-your-tapes-full-capacity.

    Above Link was fixed 1-22-2020


    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.


    Wednesday, July 15, 2015 5:51 PM
    Moderator
  • Wednesday, January 22, 2020 11:58 AM
  • Thankyou
    Wednesday, January 22, 2020 1:10 PM
  • "1) Check your tape co-location settings and make sure each Protection Group (PG) belongs to a co-location PGSet.  If a PG does not belong to a PGSet, the tapes will be marked offsite ready immediately following the backup completion.  This will force using a new tape for subsequent backups."

    Currently testing to try and get a complete tape backup for one PG on one tape.

    Sounds like I need to create a PGSet for each PG so the whole PG is backed up to one tape ?

    If the backup fails currently getting the "DPM Service terminated unexpectedly..id910" error.. is the only way to erase the tape deleting the PG, running an erase and recreate ?

    Wednesday, January 22, 2020 2:26 PM
  • Better create a new thread for your question.

    Blog: https://thesystemcenterblog.com LinkedIn:

    Wednesday, January 22, 2020 2:33 PM
  • OK willdo.. so many questions. Currently ran a test backup which failed and the Library reverted to having no slots... which was "fixed" a while back I think via the LTO Driver fix.

    Not stable at all.. :-( (Tape Backups)

    Wednesday, January 22, 2020 3:23 PM