The ideal parameter settings depend on the hardware resources available (main memory and swap space) on the one hand and the system load on the other, that is, the maximum/average number of (active) users working on an application server.
The following table serves as a guideline for setting profile parameters on UNIX platforms. In most cases the default values are also the values recommended by SAP.
Memory management on IBM AIX is different from on other UNIX systems. For this reason, setting the AIX-specific parameters is dealt with in a separate section (see Configuration for AIX).
Parameter |
Unit |
Default setting |
Comment |
Bytes |
40000000 (40 MB) |
|
|
Bytes |
2000000000 (2 GB) |
If there is a large amount of memory available, you can also increase the value if certain programs are taking up lots of memory. |
|
abap/heap_area_dia: Heap Memory Limit for Dialog Work Processes |
Bytes |
2000000000 (2 GB) |
|
abap/heap_area_nondia: Heap Memory Limit for Non-Dialog Work Processes |
Bytes |
2000000000 (2 GB) |
|
Bytes |
2000000000 (2 GB) |
You can monitor the physical memory and swap space using transaction ST06. Allocated virtual memory consists of allocated memory from: · All SAP instances · Database buffers and database processes · Operating system, special file system cache You can view this using transaction ST02 ® Detail Analysis ® Storage. |
|
Megabyte (MB) |
2040 (2 GB) |
You can increase this value, up to about 4000. |
|
8 KB blocks |
16384 (128 MB) |
Absolute upper limit: 250000 blocks (2 GB) for special applications (file system must be large enough) |
|
8 KB blocks |
2048 (16 MB) |
Absolute upper limit: 250000 blocks (2 GB) for special applications (file system must be large enough) |
|
8 KB blocks |
8192 |
Absolute upper limit: 250000 blocks (2 GB) for special applications (file system must be large enough) |
|
8 KB blocks |
32768 (256 MB) |
Absolute upper limit: 250000 blocks (2 GB) for special applications (file system must be large enough) |
|
ztta/roll_first: Size of the Initial Allocation from the Roll Area
|
Bytes |
1
|
One (1) byte means that only one small amount of memory specifically for that system is allocated and then extended memory is used. A high value (1 MB or more) may be useful if there is not a lot of extended memory available (see Recognizing and Correcting Problems). |
Bytes |
4 (4 MB) |
|
|
Kbyte
|
4096 (4 MB) |
With many small user contexts it can be useful to reduce this value (to about 1024). |