Memory Management on 64-Bit Systems (UNIX) 

An almost maintenance-free memory management solution (Zero Administration Memory Management) can be implemented on 64-bit platforms (HP-UX, AIX, Reliant, DEC-UNIX) if the 64-bit R/3 kernel is used.

This is achieved by defining an adequate default value for the virtual address space for buffer areas (program buffers, table buffers) and the user contexts (extended memory).

Approximation Computation for an R/3 Instance

64-bit executables and data segment for 60 work processes

1 GB

Program and table buffers

1.5 GB

Other shared memories

0.5 GB

Extended memory

4 GB

Heap requirement for large batch jobs

2 GB

Total

9 GB

This means that up to 9 GB of virtual address space can be assumed for each R/3 instance, and possibly with the database and all other external programs in addition.

To ensure that the maximum virtual address space requirements - also for worst case scenarios - can be met by the relevant physical background memory, approximately 20 GB of hard disk space is required for the swap area.

This means that you must configure at least 20 GB of swap space on your 64-bit system.

Given the potential savings with regard to support and consultancy, this is an extremely cost-efficient solution.

Recommended Parameters for 64-Bit Systems

The following settings are recommended for memory profile parameters:

Parameter

Recommendation:

em/initial_size_MB

1024 to 8192 (MB)

em/blocksize_KB

1024 or 4096 (KB)

ztta/roll_first

1

ztta/roll_area

3000000 (3MB)

ztta/roll_extension

2000000000 (2GB)

abap/heap_area_dia

2000000000 (2GB)

abap/heap_area_nondia

2000000000 (2GB)

abap/heap_area_total

2000000000 (2GB)

The following settings apply to HP-UX only:

Parameter

Recommendation:

es/use_shared_memory

TRUE

es/use_mprotect

TRUE

Ensure that the HP-UX operating system parameters have been set correctly. See also R/3 Note 172747.

Further information is available in the section entitled Memory Management on 64-Bit Systems: Questions and Answers.