Results 1 to 2 of 2
  1. #1
    Join Date
    Jan 2010

    Unanswered: Reall instance memory

    Hi All, I am working with db2 and AIX 7.1. I have been assigned to find out how much memory the production box needs to function normal with reasonable performance. I read from IBM document that:

    "When allocated
    Not applicable
    When freed
    Not applicable
    "The default value of instance_memory is AUTOMATIC.The AUTOMATIC setting results in a value being computed at database partition activation. The computed value ranges between 75 percent and 95 percent of the physical RAM on the system - the larger the system, the higher the percentage. For DB2 database products with memory usage restrictions, the computed"

    what does it mean " When allocated Not applicable"?
    our box has 20 GB memory so will it occupied 16 GB for instance? if database and applications did not need that much, STMM will free the memory to OS ?

    STMM and instance_memory and database_memory are AUTOMATIC.

    Really appreciate if somebody clarify this concept.

  2. #2
    Join Date
    May 2003
    The most important use of memory in DB2 is for bufferpools, so that data and indexes can be accessed from memory and not disk. The amount of memory that is optimal depends on the size of the database and type of application that is using the database. I would suggest that your company hire a consultant to who can examine all these factors at your company and provide you guidance.
    M. A. Feldman
    IBM Certified DBA on DB2 for Linux, UNIX, and Windows
    IBM Certified DBA on DB2 for z/OS and OS/390

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts