DPM 2012 - Some tapes marked as expired shortly after protection group backup finished RRS feed

  • Question

  • We have a DPM 2012 installation connected to a HP MSL4048 library with 2 LTO3 drives over fibre channel. It has the following protection groups configured with long term goals:

    DPM Configuration D2T
    PRD SharePoint Farm D2D2T
    PRD File Server D2D2T

    They are all configured the same:

    • Recovery goal 1 is weekly on Friday with 4 weeks retention
    • Recovery goal 2 is the last Friday each month with 12 months retention
    • Recovery goal 3 is the last Friday in December with 7 years retention
    • Only backups with the higher retention period run when they conflict (works well)
    • All are configured to co-locate of tape together, only where the retention periods are the same (works well)
    • Write period is 3 days, Expiry tolerance is 3 days

    The tape catalog retention is configured to prune tapes from the catalog when their retention range expires. So far so good...

    This has been working fairly until a few weeks ago when I noticed that some of the tapes had been marked as expired, instead of offsite ready. This was a little puzzling, seeing as they had just been written to! Because we are writing about 8-9TB to tape currently, this can take a while before it surfaces (and is almost impossible to test).

    This is the root of my problem...

    To make matters worse, with the way DPM works, three things now happen:

    • I have to mark them as free, unmark them as free and recatalog them to import the contents again. This means some tape recovery points are now listed under External DPM tapes instead.
    • Some tapes do not recatalog properly (Data Unavailable), which DPM says is related to them being part of a spanned tape set, without the first tape in the set being reimported.This could be a result of the co-location, maybe not.
    • Both the above points mean that the tape reporting/tracking/recovery is now patchy

    Another side effect of them being expired I presume is if these expired tapes are left too long, and you resume any backup job waiting for a free tape, they could potentially be overwritten. 

    I believe a protection group member in the PRD File Server D2D2T protection group with a corrupt/invalid tape recovery point record could be at fault here, as the last couple of tape backup jobs appear to have failed around the same items (I can't tell precisely due to the "Data Unavailable" tape content issue).

    Can anyone suggest how I can find out what is causing this problem and how I can resolve it? I have used the forcefree-tape.ps1 script on a monthly set of the same group previously, could this be related?

    The only remedial action I can think of is to completely remove the PRD File Server D2D2T protection group (also from the co-location set) and start again. Question is, will that work and will that affect other protection group member items co-located on the same tapes?

    All help appreciated.

    • Edited by Marcus Holland Tuesday, September 25, 2012 3:38 AM Omissions and corrections
    Tuesday, September 25, 2012 3:36 AM


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    Wednesday, June 26, 2013 4:50 AM