R/3 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 R/3 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_ in the R/3 system profile.

Recommended pools:

• To shift the R/3 shared memory area 6 into the R/3 shared memory pool 10, use the following parameter settings:

ipc/shm_psize_06 =-10
ipc/shm_psize_10 =

• 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 =

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