Data Segment Size (UNIX) SAP Memory Management

The data segment size restricts the size of a user context that is executed as an R/3 background job. The default value is 64 MB, which is however, not sufficient and should be increased.

Set the data segment size for a process to the following values:

UNIX Operating System	Data Segment Size
32 bit UNIX systems	Increase data segment size to approx. 600 MB.
64 bit UNIX systems (OSF/1 from Digital Equipment Corporation)	Set data segment size to at least 2048 MB.

Under IBM AIX, the maximum segment size is 256 MB; under Siemens-Nixdorf SINIX the maximum segment size is 384 MB.

You can check data segment sizes using the R/3 test program memlimits. (You must stop the R/3 server to do this.) Note the output row that appears as follows: Process xxxxx allocating. The segment size is displayed in the row Size = .

For more detailed information, also refer to the R/3 installation guide in the section covering UNIX kernel parameters.