Memory Management on 64-Bit Systems: Questions and Answers (SAP Library

Memory Management on 64-Bit Systems: Questions and Answers

When should you use the 64-bit kernel?

The following requirements must be fulfilled:

The application servers have more than 2 GB of main memory
At least 20 GB of swap space is available
Your 32-bit system is already optimally configured (EarlyWatch, GoingLive Check)
You have a development or test system where you can test the 64-bit kernel

What combinations of database software and SAP kernel are possible?

32-bit database with 32-bit SAP kernel

64-bit database with 64-bit SAP kernel

64-bit database with 32-bit SAP kernel

Not supported: 32-bit database with 64-bit SAP kernel

How can I find out if a 64-bit kernel is in use?

Choose System ® Status. The Platform ID field contains a value. The possible values and their meaning are explained in the following table.

Platform	32-bit	64-bit
DEC-Alpha	-	288
HP-UX	272	273
RM600 (Reliant)	322	323
AIX	320	324
SUN	369	370

The availability of the SAP kernel is described in the notes for the component XX-SER-SWREL.

How can I find out if a 64-bit database is in use?

Informix: choose transaction ST04 ® 'Detail analysis menu' ® 'Onstat commands' ® '-V print version'

7.24.UC3, for example, is then output. If a 64-bit database is in use, the letter F is displayed after the second period (for example, 7.30.FC3).

Caution

The version specified on the initial screen of transaction ST04 (for example, Informix-OnLine Version 7.21C1) may be incorrect! For this reason, proceed as follows:

Oracle (8.0.5 upwards): choose transaction ST04 ® 'Detail analysis menu' ® 'V$Tables' ® 'V$Version'

The string '64-bit version' is output for 64-bit versions.

Why do I need 20 GB of swap space?

64-bit technology means that the address space can now be used more generously. This minimizes maintenance requirements and the problems associated with memory management, since the size of the buffers and other areas in the shared memory can be increased considerably so that programs do not reach the system limits.

As a result, there is no risk of program crashes due to memory bottlenecks and no need for complex 'parameter tuning'.