For most of the profile parameters the default values are also correct for AIX (see Setting the Profile Parameters (UNIX)). Only with a few AIX-specific parameters might you have to change the parameter values.
The following recommendations are valid only for the 64 bit platform.
Recommended parameters in the instance profile:
Parameter |
Recommendation |
Meaning |
ES/TABLE |
SHM_SEGS |
Switches to the alternative implementation of the extended memory (EM) |
EM/TOTAL_SIZE_MB |
262144 |
The default setting as good as cancels the limitation on the extended memory. You can restrict the EM by reducing the parameter value. |
The following parameters should only be changed after consulting with SAP.
Parameter |
Default |
Meaning |
ES/SHM_PROC_SEG_COUNT |
64 |
Specifies the number of shared memory segments that are used as shared and privately. |
ES/SHM_MAX_PRIV_SEGS
|
48 |
Specifies the number of shared memory segments that are used privately.
This parameter must be lower than es/shm_proc_seg_count. |
ES/SHM_USER_COUNT |
8192 |
The maximum number of users in all open sessions. |
ES/SHM_SEG_COUNT |
8192 |
The maximum number of AIX system segments that ESSHM uses. |
ES/SHM_SEG_SIZE |
4096 |
Size of the AIX system segments (in megabytes)
Be aware that the operating system parameters also have to allow this segment size. |
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 |
78498 |
High paging rate on AIX 4.x database servers |
143646 |
AIX patches for new memory management (95454) |