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Understanding LT Recovery Goals RRS feed

  • Question

  • Hello,

    I would like to get an understanding of how I should configure my Long-Term recovery goals. Here is some background info on my environment:

    • DPM 2010
    • Co-location of data on tape: Enabled
    • Library: Dell PowerVault 124T Autoloader (single-slot drive w/ 8 tape slots)
    • 9 PGs; all are configured with the same LT protection setting
    • Current Recovery Goal: Retention range = 1 week; Backup frequency = Weekly
    • Backup schedule: Monday @ 9:00 am
    • 10 LTO-Ultrium 5 tapes (1.5 TB Native; 3.0 TB Compressed)
    • TapeWritePeriodRatio and ExpiryToleranceRange are currently at default values (I will be changing them once I understand how I need to configure my LT goals. Props to Mike Jacquet for the "Tape Offsite Ready" calculator)

    I performed the first tape backup job on 6/4/12 @ 9:00 am. The next job is set for 6/11/12 @ 9:00 am.

    LT storage goals: Weekly backup with a 1-week retention period and a 6-month backup with a 6-month retention period

    My first backup job used 3 tapes. The first tape used the full 3 TB; the second tape used 338 GB; the third tape used 1.25 TB. I'm pretty sure the reason for this is because of the TapeWritePeriodRatio not being configured correctly. Otherwise, this backup would have used only 2 tapes. Is my thinking correct on this matter?

    Right now, I only have 1 recovery goal (see above). If I configure all of my protection groups to have a second recovery goal that backs up every 6 months with a retention range of 6 months, I would expect that backup to run twice a year, with that data being retained for 6 months. Am I correct in that thinking?

    Tuesday, June 5, 2012 10:08 PM

Answers

  • Hi

    I believe you understand the concepts correctly.  I'm questioning why the tape backup on 6-4-12 used three tapes, even with default settings, all the backups would have fit on two tapes.   Please see my blog at http://blogs.technet.com/b/dpm/archive/2012/05/14/things-you-can-do-to-help-data-protection-manager-utilize-your-tapes-full-capacity.aspx to see if you are getting I/O error under the covers causing the tape to be closed out prematurely.


    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.

    • Marked as answer by MSS_AxiomEPM Tuesday, July 10, 2012 2:53 PM
    Wednesday, June 6, 2012 2:40 AM
    Moderator
  • Hi,

    <snip>
    Does the TapeWritePeriodRatio start from the time the tape backup kicks off?
    >snip<

    The timer starts based on the first recovery written to tape, and that recovery point time will be the last disk based recovery point available at the time the LT tape backup job started.  In your case, the last disk based RP is on Saturday at XX time.  When that recovery point is written to tape, it will show Saurday at XX time ans that is what is considered when calculating how long to use a tape based on the TapeWritePeriodRatio.

    Now, the TapeExpiryTolerance and TapeWritePeriodRatio together determine how long a tape can be used before marking it offsite ready.  There is nothing stopping you from removing a tape from the library before being marked offsite ready.  So you can remove the tapes after backups complete on Monday and not worry about it. 


    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.


    Tuesday, July 10, 2012 3:23 PM
    Moderator

All replies

  • Hi

    I believe you understand the concepts correctly.  I'm questioning why the tape backup on 6-4-12 used three tapes, even with default settings, all the backups would have fit on two tapes.   Please see my blog at http://blogs.technet.com/b/dpm/archive/2012/05/14/things-you-can-do-to-help-data-protection-manager-utilize-your-tapes-full-capacity.aspx to see if you are getting I/O error under the covers causing the tape to be closed out prematurely.


    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.

    • Marked as answer by MSS_AxiomEPM Tuesday, July 10, 2012 2:53 PM
    Wednesday, June 6, 2012 2:40 AM
    Moderator
  • OK, things are definitely getting better with using LT storage. The link to your blog and the "Tape Offsite Ready Calculator" have proven to be very helpful. I've been able to get all data to back up to two tapes. The one area where I'm having an issue is trying to get my TapeWritePeriodRatio setting right.

    Right now, I have short term disk storage scheduled Monday-Saturday, with Sunday as my day for long term tape storage. I have the TapeExpiryTolerance set at .5 (50%). I had set the TapeWritePeriodRatio to .1 (10%), but that doesn't seem to be enough time. Does the TapeWritePeriodRatio start from the time the tape backup kicks off?

    My goal is to have tape backups kick off on Sunday and have them ready to go offsite at the end of the day on Monday. I want to make sure that all data gets backed up to the two tapes as well. The TapeExpiryTolerance setting is OK. It's the TapeWritePeriodRatio that I'm having a heck of a time with. If my tape backup kicks off at 5:00 PM on Sunday (there's enough data to write to tape that the operation will continue into Monday), what should I set my TapeWritePeriodRatio to?

    Thanks in advance for all your help Mike! You're an asset to this board!

    Tuesday, July 10, 2012 3:08 PM
  • Hi,

    <snip>
    Does the TapeWritePeriodRatio start from the time the tape backup kicks off?
    >snip<

    The timer starts based on the first recovery written to tape, and that recovery point time will be the last disk based recovery point available at the time the LT tape backup job started.  In your case, the last disk based RP is on Saturday at XX time.  When that recovery point is written to tape, it will show Saurday at XX time ans that is what is considered when calculating how long to use a tape based on the TapeWritePeriodRatio.

    Now, the TapeExpiryTolerance and TapeWritePeriodRatio together determine how long a tape can be used before marking it offsite ready.  There is nothing stopping you from removing a tape from the library before being marked offsite ready.  So you can remove the tapes after backups complete on Monday and not worry about it. 


    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.


    Tuesday, July 10, 2012 3:23 PM
    Moderator
  • Ok, that makes sense. And that's good to know about removing the tapes after backups complete. Thanks again!!!
    Tuesday, July 10, 2012 3:29 PM