Application Servers with Over 50 Users in Memory Management

The correct configuration for the memory management system in large R/3 application servers depends on the several factors. SAP can therefore not give any recommendations for the standard configuration. However, you can calculate your own approximate values by referring to the information in this unit and in the other units that are referred to.

To determine the required resources for the host system, contact the SAP Competence Center of your hardware partner Then you can configure the R/3 Server by setting the R/3 memory management parameters in the R/3 system profile.

Main Memory and Swap Space on the Host System

Resource	SAP Recommendation
Size of the swap file or virtual memory paging file	Minimum: the greater of the 2 following numbers: 2-3 GB three times the main memory In each case, this must be larger than the sum of: the required R/3 swap space (can be approximated using the program sappfpar; see Additional Swap Space Requirements) the memory requirements of the operating system to be safe, at least 200 MB free memory area when executing the operation
Main memory	Guidelines: Central system with all services, no database: 180 MB plus 5.7 MB per active user or at least 512 MB With database: Add 150 MB plus 0.3 MB per active user Application server: 120 MB plus 5.3 MB per active user More memory increases performance. Also contact your hardware partner or the SAP Competence Center for your hardware partner.
Work processes (Windows NT)	See Determining the Number of Work Processes

R/3 Profile Parameters

How to use the individual parameters is described in Profile Parameters of the Memory Management.

Parameter	Recommended Value
abap/heaplimit	20000000 (20 mil. bytes)
abap/heap_area_dia	2000000000 (2 GB)
abap/heap_area_nondia	Platform dependent, see the parameter documentation
abap/heap_area_total: Limit for Heap Memory	2000000000 (2 GB); see the parameter documentation
em/initial_size_MB: Size of the Extended Memory Pool	UNIX: 5 MB per active user + 1.5 MB per user; minimum 256 MB Windows NT: 8192
em/stat_log_size_MB: Statistics - User Context Size	20
em/stat_log_timeout: Statistics - User Context Size	600
rdisp/ROLL_MAXFS: Maximum Roll File Size	UNIX: 32768 (32768 8KB blocks) Windows NT: the same value as rdisp/ROLL_SHM
rdisp/ROLL_SHM: Roll Buffer Size	UNIX: 8192 blocks or 1 MB per active user up to a maximum of 16.500 blocks (100 MB), unless more memory is required (analysis with Transaction ST02) Windows NT: 128 blocks (1 MB, per active user)
rdisp/PG_MAXFS: Maximum Size of the R/3 Paging File	UNIX: 32768 (32768 8KB blocks) Windows NT: the same value as rdisp/PG_SHM
rdisp/PG_SHM: Size of the Paging Buffer	UNIX: 1024 blocks Windows NT: 13 blocks (0,1 MB, per active user)
ztta/roll_area: Roll Area	UNIX: 6500000 (6,5 mil. bytes) Windows NT: 1000000 (1 mil. bytes)
ztta/roll_first: Size of the Initial Allocation from the Roll Area	UNIX: 1000000 (1 mil. bytes) If more than 5 MB of extended memory is available per user (em/initial_size_MB), you can set this value to 1 (1 byte). Windows NT: 1 (1 byte)
ztta/roll_extension: Limit for Extended Memory	128000000 (128 mil. bytes),except for background servers under IBM AIX and Siemens-Nixdorf SINIX You can find more information in the parameter documentation

The settings listed here are recommended base values that you may however, have to change if you monitor and optimize your R/3 System. For more detailed information, see Monitoring the Memory Management System and Profile Parameters of the Memory Management.

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