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DB utilization on TSM 5.5

Discussion in 'TSM Operation' started by pjackson1, Apr 25, 2012.

  1. pjackson1

    pjackson1 New Member

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    Occupation:
    Data Storage Specialist
    Location:
    Minneapolis, MN
    Hi, I'm trying to understand why I get such different DB utilizations between two similar TSM 5.5 servers from an occupancy standpoint. Here are the differences between them:

    -----------| Server A --| Server B
    --------------------------------------
    Occupancy-| 270 Million | 272 Million
    DB Used----| 144 GB ---| 123 GB
    DB Total----| 174 GB ---| 174 GB
    Client Nodes| 1,200 -----| 600


    I'm trying to understand what goes into DB usage. So far I have only been able to find that it's: 400-600 bytes per backed up file + 200 bytes per active file + 200 bytes per bkp-copy pool version along with 25% for overhead. I've looked at the activity log size and Server A is at 2GB and Server B is at 1GB so that only accounts for 5% of the increased size of Server A.

    Any ideas? What am I missing?

    Thanks!
     
  2.  
  3. chad_small

    chad_small Moderator

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    What you have to look at is the amount of space that would be freed up with a reorg (DB Dump, Load/Audit). With the one serve having 1200 clients it probably has more files processed and expiring on a daily basis so the amount of space recoverable from a reorg could be the difference. post a Q DB F=D on both.
     
  4. pjackson1

    pjackson1 New Member

    Joined:
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    Occupation:
    Data Storage Specialist
    Location:
    Minneapolis, MN
    Server A:
    Available Space (MB): 174,048
    Assigned Capacity (MB): 174,048
    Maximum Extension (MB): 0
    Maximum Reduction (MB): 10,820
    Page Size (bytes): 4,096
    Total Usable Pages: 44,556,288
    Used Pages: 37,226,371
    Pct Util: 83.5
    Max. Pct Util: 84.5
    Physical Volumes: 24
    Buffer Pool Pages: 262,144
    Total Buffer Requests: 254,602,593
    Cache Hit Pct.: 99.35
    Cache Wait Pct.: 0.00
    Backup in Progress?: No
    Type of Backup In Progress:
    Incrementals Since Last Full: 0
    Changed Since Last Backup (MB): 7,802.31
    Percentage Changed: 5.37
    Last Complete Backup Date/Time: 04/25/2012 10:47:26
    Estimate of Recoverable Space (MB):
    Last Estimate of Recoverable Space (MB):

    Server B:
    Available Space (MB): 174,048
    Assigned Capacity (MB): 174,048
    Maximum Extension (MB): 0
    Maximum Reduction (MB): 8,160
    Page Size (bytes): 4,096
    Total Usable Pages: 44,556,288
    Used Pages: 31,450,135
    Pct Util: 70.6
    Max. Pct Util: 95.4
    Physical Volumes: 24
    Buffer Pool Pages: 262,144
    Total Buffer Requests: 3,160,066,614
    Cache Hit Pct.: 99.00
    Cache Wait Pct.: 0.00
    Backup in Progress?: No
    Type of Backup In Progress:
    Incrementals Since Last Full: 0
    Changed Since Last Backup (MB): 3,083.70
    Percentage Changed: 2.51
    Last Complete Backup Date/Time: 04/25/2012 13:03:32
    Estimate of Recoverable Space (MB):
    Last Estimate of Recoverable Space (MB):
     
  5. pjackson1

    pjackson1 New Member

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    Occupation:
    Data Storage Specialist
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    I spoke with someone today that suggested, if possible, to get the size of the tables in the database. Does anyone know how to do that? I found an interesting mail archive (http://www.mail-archive.com/adsm-l@vm.marist.edu/msg09065.html) which suggests somehow using the show objd and show tree commands but it wasn't clear how to translate the output into actual storage utilization.
     
  6. rowl

    rowl Member

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    I ran a question about this by TSM support years ago and the response I got was along these lines. The TSM DB releases space during expiration processing, but that is not reflected in the q db output. TSM will reuse that space which may give the illusion that the DB is not growing as new data is being backed up because of the reuse of expired pages. By doing an unload/reload of the DB you can reclaim this free space but that process is so time consuming it generally isn't worth the effort.

    -Rowl
     

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