DB2 Basics: Backups of Data and Configuration

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4 Responses

  1. Somraj Chakrabarty says:

    Hi Ember,

    Could you please help me understanding the clause “Open num sessions” in db2 database backup command using TSM and backup restore client.Is it increasing the backup performance or take the backup simultaneously in multiple streams(divided the backup image into segments).In our environment database backup command is using the clause “open 2 sessions using TSM” and I can see there are 3 entries in recovery history file and during checking the backup image with db2ckbkp,the check is being done 3 times.So is it checking the same image 3 times or it is just 3 segments of a backup image.Could you please let me know.

    Regards
    Somraj

    • Ember Crooks says:

      I haven’t worked with TSM in several years, so I’d have to play with it to understand. You can use db2adutl commands to extract a backup image to disk (assuming you have disk with enough space) so you can play with it in a more familiar environment. I know that specifying more than one session only helps performance if you have fully separate paths to your TSM server – specifying multiple sessions when it all goes over the same adapters and same link is not going to make much difference.

      If backing up to disk, you can specify multiple locations and split your backup file into multiple pieces – to gain efficiencies of separate I/O paths or deal with not having a single large enough disk.

  2. Vasu says:

    Could you please post DB2 command to take offline TSM DB backup with multiple streams to disk(single and multiple paths)?

    • Ember Crooks says:

      You can either take the backup to TSM or to disk, not both. There are commands to extract a backup taken to TSM to disk using db2audtl. Db2 commands do not exist to move a backup from disk to TSM, but I believe TSM would have commands for that.

      If you want to take a backup to multiple disk locations, you would use syntax like this:

      db2 backup database SAMPLE to /disk1, /disk2, /disk3 ...

      If you want multiple TSM sessions to be used, you would use syntax like this:

      db2 backup database SAMPLE use TSM open 3 sessions ...

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