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DPM 2007 SP1 jobs to tape and compression RRS feed

  • Question

  • Does it make sense that I am fitting over 5 TB's of data on two LTO4 tapes?  (800 GB uncompressed/1.6 TB compressed)?

    I am using hardware compression.  The data set consists of about 500 GB of SQL data, 1 TB of flat files and folders and the rest are HyperV VHD files that are in a shutdown state (Not using DPM agent to back up live guest).

    I thought I should only expect no more than 2:1 compression but apparently that notion is wrong or something is terribly wrong with my DPM server.

    I really wish there was a utility to help me see how much data is on my tape.

    Tuesday, September 28, 2010 3:12 PM

Answers

  • Hi,

    Check with the drive manufacturer and see what the published compression ratio is, it's conceivable that you may get better than 2:1 based on data types.   You can also enable verification so DPM will verify the data is good after backup to make you feel better.   And, like any good backup operator, do periodic test restores.


    Regards, Mike J. [MSFT] This posting is provided "AS IS" with no warranties, and confers no rights.
    Monday, October 4, 2010 8:36 PM
    Moderator

All replies

  • Hi,

    Check with the drive manufacturer and see what the published compression ratio is, it's conceivable that you may get better than 2:1 based on data types.   You can also enable verification so DPM will verify the data is good after backup to make you feel better.   And, like any good backup operator, do periodic test restores.


    Regards, Mike J. [MSFT] This posting is provided "AS IS" with no warranties, and confers no rights.
    Monday, October 4, 2010 8:36 PM
    Moderator
  • Manufacturer states 2:1

    I found it out I was getting 3:1 compression but can probably be explained by the "empty disk space" in the HyperV guests.

    We are doing test restores (random) of data on a monthly basis.

    Monday, October 4, 2010 11:34 PM