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  1. #1
    Join Date
    Apr 2015
    Posts
    4
    Provided Answers: 1

    Answered: Native db2 backup compression

    Hello DB2 experts

    I have an SAP application/database server (sandbox)

    OS: SUSE Linux Enterprise Server 11 (x86_64), VERSION = 11, PATCHLEVEL = 2
    db2: DB2 v9.7.0.9, at Fix Pack 9.
    SAP: ECC6 EHP 7 SP2

    I'm using db2 online backup to backup the database. i.e. db2 backup database TCK online to /stage/db2_TCK_backup compress include logs WITHOUT PROMPTING

    With compression turned on my backup file size is 61 GB. Without compression the backup file size is 204 GB.

    With compression there is a 70% reduction in file size which is hard to believe.

    Have any of you seen this kind of compression?

  2. Best Answer
    Posted by db2mor

    "I have seen equivalent compression on a SAP database backup yes, around 72% if memory serves (with DB2 V9.7 on AIX) for dev, test, prod environments.
    Note that none of the tables were using any form of compression at that time.
    This compression ratio was hugely beneficial to the operational folks, as it also slashed the duration of the backup.
    We carefully verified the recovery from the compressed backups also."


  3. #2
    Join Date
    Feb 2004
    Location
    In front of the computer
    Posts
    15,579
    Provided Answers: 54
    I typically see compressed backups taking anywhere from 8 to 45% of the size of the original data, with the average being close to 15%

    The amount of compression varies quite a bit depending on the amount of entropy (redundancy) that exists in the uncompressed backup file. Some backups/data compress much better than others, but 30% wouldn't concern or impress me.

    -PatP
    In theory, theory and practice are identical. In practice, theory and practice are unrelated.

  4. #3
    Join Date
    Apr 2012
    Posts
    1,035
    Provided Answers: 18
    I have seen equivalent compression on a SAP database backup yes, around 72% if memory serves (with DB2 V9.7 on AIX) for dev, test, prod environments.
    Note that none of the tables were using any form of compression at that time.
    This compression ratio was hugely beneficial to the operational folks, as it also slashed the duration of the backup.
    We carefully verified the recovery from the compressed backups also.

  5. #4
    Join Date
    Nov 2011
    Posts
    87

    Compression time too long

    my DB Size is 550GB, after compression it comes to 350GB. Normal backup takes one hour but compression backup takes four hours. (DB2 9.7 on Windows 2008 R2 / 6 CPU / 8GB RAM)

    during the backup plenty of free resources. WHY?

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