Configuration for iSeries

For information about how the memory management system is implemented on iSeries, see Memory Management on iSeries.

In the tables below, you will find information about the necessary settings for the memory management system.

·        Check that your host system fulfills the SAP recommendations for main storage and free space in the auxillary storage pool (ASPs).

Check the resources and system-specific requirements on all host systems on which a server is to be installed. For more information, see Checking the Hardware and Operating System of the Host System.

·        The profile parameters that the memory management system uses are set automatically and are stored in the instance profile used by each SAP NetWeaver Application Server in your system. For more information, see Profiles.

If you modify the profiles directly with a system editor, you must perform an error check. For more information, see Checking the Hardware and Operating System of the Host System.

The values listed in the following table for the host systems and servers should ensure the best possible operation of your SAP NetWeaver Application Server.

Main and Unprotected Storage on the Host System


SAP Recommendation

Free storage area ASP 1

Minimum: 2 GB
Recommend 4-6 GB

Main storage

512 MB is sufficient for approx. 15 dialog users.
1024 MB is sufficient for approx. 50 dialog users.

You will achieve performance advantages with higher values.

These values are valid for hosts on which only one SAP system runs. If other SAP systems run on the host, contact the Hardware Competence Center or your system consultant.

Storage pool 2

All SAP jobs run in pool 2 according to the default values. Therefore, make as much space as possible available for pool 2. 250 MB is the absolute minimum.

Recommended Profile Parameters


Recommended Value


40000000 (40 mil. bytes)


2000000000 (2 GB)


2000000000 (2 GB)

abap/heap_area_total: Limit for Heap Memory

2000000000 (2 GB)

em/initial_size_MB: Size of the Extended Memory Pool


Minimum 64 MB (5 MB per user)

em/stat_log_size_MB: Statistics - User Context Size


em/stat_log_timeout: Statistics - User Context Size


rdisp/ROLL_MAXFS: Maximum Roll File Size


rdisp/ROLL_SHM: Roll Buffer Size


rdisp/PG_MAXFS: Maximum Size of the SAP Paging File


rdisp/PG_SHM: Size of the Paging Buffer


ztta/roll_area: Roll Area

16773120 (16 MB roll area per internal mode)

ztta/roll_first: Size of the Initial Allocation from the Roll Area


ztta/roll_extension: Limit for Extended Memory

2000000000 (2 GB extended memory per user)


Recommended Value (Use)


20 (Size above which the user context is logged for statistical purposes)


600 (Interval in which statistics are gathered for the user context size)

The values listed here are recommended basic values. In the course of monitoring and optimizing your SAP system, you may have to change these values under certain circumstances. For more information, see Monitoring the Memory Management System and Temporary Memory on iSeries.

Check the changes to the system profiles using the program rspfpar. For more information, see Checking the Hardware and Operating System of the Host System.