Tape retention confusion RRS feed

  • Question

  • I'm a little confused on what I see happening on DPM 2010 tape retention.  I have a protection group that has 30 short-term days on disk before I write for Long term retention on tape.  When I first set this up I was only going to disk first.  Once I added my tape library a month later, I wanted to continue the retention by writing to tape.  I modified the policy to include the long-term retention for another month on top of the 30 days on disk.  When the first backup to tape occurred, it picked the latest backup performed last night to write to tape, not the one that was 30 days old already on disk.  This does not make sense to me. 

    To state it another way.  Why would you start a backup on disk for 30 days,(day 1 to 30), at the end of 30 days you want to keep protection of the stuff backed up on the 1st on tape because the day 31 will start overwriting day 1.  Instead I get day 30 written to tape.

    Hope that makes sense.    


    Thursday, January 27, 2011 1:06 AM


  • Tape backup always picks up the latest data. Your backup policy would look something like this.

    Disk Backup  : Daily backup, Retention Range : 30 days

    Tape Backup: Weekly backup, Retention Range: 1 Year (Probably 2 months in your case)


    If you had started both long-term and short-term protection at the same time, 1st  tape would still have the data which gets overwritten on disk on day 31.

    I hope it makes sense.



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    Friday, January 28, 2011 11:57 AM