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SAP Memory Managemt parameters on AIX 6.1

Hello,

please, can you explain me the significance of parameters ES/SHM_MAX_PRIVS_SEGS and ES/SHM_PROC_SEG_COUNT? I know that both parameters are described in SAP note #789477 and others, but I can not find the meaing of the two parameters.

Why is it important to setup the number of shared private segments?

Best regards

Martin Hucl.

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1 Answer

  • Sep 21, 2010 at 10:50 AM

    Hello Martin,

    the meaning of the parameters is:

    ES/SHM_PROC_SEG_COUNT : Specifies the number of shared memory segments that are used as shared and privately.

    ES/SHM_MAX_PRIV_SEGS: Specifies the number of shared memory segments that are used privately.

    As mentioned in note 789477, the ztta/roll_extension = ES/SHM_MAX_PRIV_SEGS * ES/SHM_SEG_SIZE * 1024 * 1024

    hope it helps,

    Mercedes

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    • Hello Martin,

      the user context is stored in Extended Memory, if If the user context still requires additional memory (apart from roll & Extended memory), it is assigned heap memory

      With the Alternative Memory Management in AIX, multiple "windows" of extended memory are created where virtual shm segments for each user context. The size of these segments is determined by ES/SHM_SEG_SIZE and each user context can access up to ES/SHM_PROC_SEG_COUNT.

      hope it helps,

      Mercedes