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  1. #1
    Join Date
    Nov 2011
    Location
    Chennai
    Posts
    27

    Unanswered: Backup speed and time

    Hi All,

    I have some doubts regarding the db backup.

    1) How backup speed will be calculated ?
    DB size/ time taken or Backup size/time taken.

    2) How the HWM usage impacts the backup time?
    i heard backup starts reading from page 0 to hwm'd page if that is the case .. i have some 100GB locked up in HWM will this enhance the backup time taken ?

    db2level -> v9.5 Fix Pack"8"

    any help will be greatly appreciated


    thanks
    Thawfii88

  2. #2
    Join Date
    Oct 2004
    Location
    DELHI INDIA
    Posts
    338
    1> Backup speed you need to calculate with size of the backup created w.r.t the total time consumed.


    2> W.r.t performance of the backup, you need to consider facts like DISK speed where you are taking the backup, network speed if you are using TSM API, Database CPU and related configuration parameters, related config parameters for running utilities ( e.g. UTIL_HEAP , UTILITY Impact Priority etc ).

    Jayanta Datta
    DB2 UDB DBA
    IBM India, Global Delivery
    New Delhi

  3. #3
    Join Date
    Nov 2011
    Location
    Chennai
    Posts
    27
    Backup is written to the disk.
    frequency 1902096000 Processor Speed x 10 processor
    UTIL_HEAP = 20480

    can anyone explain the impact of HWM in tablespaces on backup
    Last edited by thawfii88; 07-25-12 at 08:04.

  4. #4
    Join Date
    May 2003
    Location
    USA
    Posts
    5,737
    There is some impact on having a HWM well above current utilization, but I don't have any specific numbers on that. If a tablespace is created in 9.7+, it is easy to lower the the HWM, otherwise it is difficult.

    One way to improve performance is to write the backup to multiple files, each on a different mountpoint, assuming that each mountpoint has different disk spindles. See the Command Reference for more info on this.
    M. A. Feldman
    IBM Certified DBA on DB2 for Linux, UNIX, and Windows
    IBM Certified DBA on DB2 for z/OS and OS/390

  5. #5
    Join Date
    Nov 2011
    Location
    Chennai
    Posts
    27
    Thanks all .. thanks for your guidance !!

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