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Why 2 backups using DAG? RRS feed

  • General discussion

  • When configuring the protection group for an Exchange 2010 DAG all recommendations I've seen point to selecting the Exchange DB which selects all DAG members. When this is done say for a 2 node DAG there is a section to have one member be the Full Backup and the other to be the Copy Backup.

    So once the protection begtins working I am seeing both DAG members in the protection group which have backed up the data. My question is:

    Is DPM essentially backing up both members therefore I have 2 copies of the same data using up twice the space?

    Friday, June 29, 2012 5:07 PM

All replies

  • Hi mtnman,

    Microsoft recommends a minimum of two copies of a Exchange DAG Database to take backup.

    when you configure your DAG backup you have the possibility to setup 2 types of settings :
     
    - Full Backup : Truncates the logs
     
    - Copy Backup : Keeps the logs intact
      
    You must have only one copy of your database in the Full Backup type. This will truncate the logs and then Exchange will replicate the changes to other copies of your database. 

    Choosing active or passive database copies for full/copy backup is depending on your goals and the performances you want to achieve. Doing backup on two copies involves twice the space on your DPM server.

    Stephane.


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    Sunday, July 1, 2012 12:19 PM
  • I see, that makes sense. Thanks.

    So can anyone think of why the old recovery points might not be deleting on the Full Backup but does on the Copy Backup? I have a DB that is used for journaling that sends to an offsite archive so I only set it to keep one Replica and do a recovery point at 8:00 PM and keep only one copy. For some reason it hasrecovery points going back 3 days with 69 recovery points. I'd expect to see less than 24.

    Thursday, July 5, 2012 11:23 PM
  • Hi mtnman,

    Could you provide your backup settings for both Full Backup and Copy Backup database ? (FE, Sync, retention)

    Stephane.


    Please remember to click “Mark as Answer” on the post that helps you. This posting is provided "AS IS" with no warranties. knowledge is valid only if it is shared by All.

    Friday, July 6, 2012 8:03 AM
  • Both DAG nodes are in the same protection group.

    • Short term using disk
    • One node is Full the other is copy backups
    • Retention 1 day
    • Frequency every hour
    • Express full at 8:00 PM

    I did try running the prunshadowcopies2010.ps1 yesterday and the total recovery points reduced to 58 when I looked this morning so it looks like the last recovery point is still 3 days ago so something did prune but it still doesn't look accurate.

    Here is what it looks like:

    Node with full protection

    • Oldest recovery point 7/3 and latest recovery point 7/6
    • Total recovey points is 58

    Node with copy protection

    • Oldest recovery point 7/4 and latest recovery point 7/5
    • Total recovery points is 2
    Friday, July 6, 2012 12:53 PM
  • this is strange behaviour...

    According to your settings for a retention goals of 1 day:

    • for full backup you should have no more than 24 RP (12 RP day 7/5 + 12 RP day 7/6)
    • for Copy backup you should have no more than 2 RP (1 RP day 7/5 + 1 RP 7/6)

    Did you made manual Recovery Point ?


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    Friday, July 6, 2012 2:28 PM
  • Yes, I made a manual recovery point last week after I first created and after the initial one due to logs not truncating.
    Friday, July 6, 2012 7:01 PM
  • Did you try to unprotect and protect again your datas ?

    If yes, take a look at this link : http://blogs.technet.com/b/dpm/archive/2010/11/03/protect-unprotect-protect-unprotect-understanding-how-dpm-2010-retention-works.aspx

    I hope this will be relevant with your issue.

    Stephane


    Please remember to click “Mark as Answer” on the post that helps you. This posting is provided "AS IS" with no warranties. knowledge is valid only if it is shared by All.

    Friday, July 6, 2012 8:41 PM