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4 replies Latest Post - ‏2007-11-02T15:44:29Z by SystemAdmin
SystemAdmin
SystemAdmin
17917 Posts
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Pinned topic Redirect Restore script Performance

‏2007-11-02T09:08:10Z |
DB2 v9 offers new functionality to create a redirected restore script. Until v9 the customer had to develop their own solution for this.

I performed some testing on t25/ddadb595 with the following syntax and was very surprised to see that DB2 read the entire backup image and not just the header.
It was my understanding everything required is contained in the header, so I was very surprised to see this.

Documentation
http://publib.boulder.ibm.com/infocenter/db2luw/v9/index.jsp?topic=/com.ibm.db2.udb.admin.doc/doc/t0021521.htm

Syntax used
db2 restore db $sid load /usr/tivoli/tsm/tdp_r3/db264/libtdpdb264.a taken at 20071027072522 redirect generate script /tmp/redirect.txt

TSM server info showing a considerable portion of the backup was accessed
tsm: DDTSM03>q sess

Sess Comm. Sess Wait Bytes Bytes Sess Platform Client Name
Number Method State Time Sent Recvd Type









1,161,1 Tcp/Ip SendW 0 S 4.7 G 370 Node TDP R3 SAP_T25
54

I'm sure the necessary information is contained in the backup header.
That is confirmed when we restore a backup onto empty filesystems. The database recognizes this and creates the tablespaces with the information read from the first 100 or so mb from the backup header.

What are you thoughts?
Updated on 2007-11-02T15:44:29Z at 2007-11-02T15:44:29Z by SystemAdmin
  • SystemAdmin
    SystemAdmin
    17917 Posts
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    Re: Redirect Restore script Performance

    ‏2007-11-02T09:12:37Z  in response to SystemAdmin
    Hi,

    are you using automatic storage tablespaces within your database?

    Regards,
    Thomas
    • SystemAdmin
      SystemAdmin
      17917 Posts
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      Re: Redirect Restore script Performance

      ‏2007-11-02T09:40:42Z  in response to SystemAdmin
      Hi Thomas,

      I confirm that the utilized backup image wasn't automatic storage enabled.

      All the point here is to enhance the performance timing for such recovery operation especially when multi-terabytes database are involved.

      Thanks for you analysis,

      Regards,
      Mohamed Redouane (Nestlé - IBM)
    • SystemAdmin
      SystemAdmin
      17917 Posts
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      Re: Redirect Restore script Performance

      ‏2007-11-02T09:51:08Z  in response to SystemAdmin
      Hi Mohamed,

      as I saw in the sample DB2 backup command you posted you are using the product Tivoli Data Protection for R/3 for backing up your database.
      That product has a smart built-in automatic redirected restore function. If you need further information on that, please send my an email to my IBM account (Thomas Ritter, Data Protection for mySAP development).

      Regards,
      Thomas
      • SystemAdmin
        SystemAdmin
        17917 Posts
        ACCEPTED ANSWER

        Re: Redirect Restore script Performance

        ‏2007-11-02T15:44:29Z  in response to SystemAdmin
        Thomas,

        We just made a new test by running "redirect generated script" restore option using TSM and we found out that few Mbs are read from the backup image.

        This fact leads us to think that "redirect generated script" algorithm is third-party vendor library dependent.

        Is there a way to make TDP built-in automatic redirected restore function working like TSM one?