Shared Memory ID under IBM AIX (SAP Library - SAP Memory Management (BC-CST-MM))

Shared Memory ID under IBM AIX

A shared memory ID is used for each shared memory segment (256 MB) used in a work process. There is a maximum of 10 shared memory IDs for each process. If the parameter em/initial_size_MB is set to a value up to 256 MB, an ID is used. However, if the value for this parameter is set between 256 and 512 MB, 2 IDs are used, and so on.

You must reduce the number of SAP shared memory areas so that the memory management system can be used under AIX. This includes the areas in pools. For this, set the parameters ipc/shm_psize_<nn> in the SAP system profile.

Recommended pools:

To shift the SAP shared memory area 6 into the SAP shared memory pool 10, use the following parameter settings:

ipc/shm_psize_06 =-10
ipc/shm_psize_10 = <newly suggested size from SAP program sappfpar>

If the shift from area 6 is insufficient, shift area 41 to 49 into pool 10. Shared memory pool 4 is no longer required.

ipc/shm_psize_41 =-10
...
ipc/shm_psize_49 =-10...
ipc/shm_psize_10 = <newly suggested size from SAP program sappfpar>

For more details on this subject, refer to the SAPNet note Notes 98084, 95260, and 95454 in the SAP online system.

Configuration for AIX describes how to configure Memory Management under AIX.