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  1. #1
    Join Date
    Sep 2012
    Posts
    177

    Unanswered: Allocation of pages in bufferpool in partition environment.

    Hi all,

    In our setup:
    ==========

    Db2 version 9.7 with fixpack 4 for redhat linux with version 5.5

    With 2 partition databases

    Question:
    ========

    Allocation of pages in Bufferpool for the partiton databases?

    Db: STG1

    Data tables assigned to buffer pool of 32k page size, 32 block size and 1000 size. Need advise on block size and numer of pages to allocate.

    Control tables assigned to buffer pool of 8k page size, 32 block size and 1000 size. Need advise on block size and number of pages to allocate

    Could you please give the suggestion?

    Thanks in advance
    laxman..

  2. #2
    Join Date
    May 2003
    Location
    USA
    Posts
    5,737
    1000 pages is very small. The total of all bufferpool memory should be about 50-75% of all real memory on the server. DB2 does not like virtual memory, so make sure you have real memory available. Also, make sure you understand that if there are four logical DPF partitions on a server, and 2 databases on a DPF system, and if both databases are configured with the same bufferpool sizes, then there will be eight sets of bufferpools on the server, so take that into consideration when ensuring you don't go over the maximum amount of real memory.

    Regarding data bufferpools vs index bufferpools, a starting value for number of pages might be to allocate 3/4 of memory for data and 1/4 for indexes. But it is not clear if you have your system set up with separate bufferpools for data and indexes. Not sure what you mean by "control tables," but there is no benefit to making bufferpools larger than the total amount of data in those tables, since you would be wasting valuable memory.

    For block size, a good starting number would be about 3% of total pages for that bufferpool, which would have to be calculated after you figured out all the other numbers.
    Last edited by Marcus_A; 09-28-12 at 09:33.
    M. A. Feldman
    IBM Certified DBA on DB2 for Linux, UNIX, and Windows
    IBM Certified DBA on DB2 for z/OS and OS/390

  3. #3
    Join Date
    Sep 2012
    Posts
    177
    Hi Marcus,

    As per our setup can i allocate the Npages like this:

    db2 "CREATE BUFFERPOOL "BUFF2" immediate DATABASE PARTITION GROUP "vic01" SIZE 200 PAGESIZE 8192"

    db2 "CREATE BUFFERPOOL "BUFF2" immediate DATABASE PARTITION GROUP "vic01" SIZE 100 PAGESIZE 32768"

    Thanks,
    laxman.

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