Configuration for AIX

Prerequisites

For most of the profile parameters the default values are also correct for AIX. Only with a few AIX-specific profile parameters might you have to change the parameter values.

Procedure

Recommended profile parameters in the instance profile:

Profile Parameter

Recommendations

Explanation

ES/TABLE

SHM_SEGS

Switches to the alternative implementation of the extended memory.

EM/TOTAL_SIZE_MB

512000

By decreasing the profile parameter, the extended memory can be limited.

The following profile parameters should only be changed after consulting with SAP.

Profile Parameter

Default

Meaning

ES/SHM_PROC_SEG_COUNT

3

Specifies the number of shared memory segments that are used as shared and privately.

ES/SHM_MAX_PRIV_SEGS

2

Specifies the number of shared memory segments that are used privately.

ES/SHM_MAX_SHARED_SEGS

(($(em/global_area_MB)+ $(abap/shared_objects_size_MB)+ $(rtbb/buffer_length)/1024+ $(zcsa/table_buffer_area)/1024/1024)/ $(ES/SHM_SEG_SIZE)+ 1)

Specifies the number of shared memory segments.

ES/SHM_USER_COUNT

1024

The maximum number of users in all open sessions.

ES/SHM_SEG_COUNT

1024

The maximum number of AIX system segments that ESSHM uses.

ES/SHM_SEG_SIZE

4096

(4GB)

Size of the AIX system segments (in megabytes)

These recommendations depend not only on whether the alternative method of implementing extended memory is active, but also on the AIX version used.

The following SAP Notes relate to memory management under AIX:

Note Number

Short Text

789477 Information published on SAP site

Large extended memory on AIX (64-Bit) as of Kernel 6.20

174882 Information published on SAP site

Shortage of shared memory segments in AIX