Zero administrator memory in SAP memory mangement

[Former Member]

Guys,

Could you help me regarding Zero adminstrator memory in memory management..

Thanks and Regards,

Phani.

[former_member188883 · Accepted solution]

Hi,

The basis for the Zero Administration Memory Management on Windows is the dynamic extended memory. The technique provides you with a nearly unlimited memory resource. Initially, the extended memory is set to the size of the profile parameter phys_memsize (PM). If the user requires more memory, extended memory extends itself in steps from "PM / 2" up to the set limits in the profile parameter em/max_size_MB, or until the address space in the Windows page file is used up. By setting the default value for em/max_size_MB to 20000 MB, the size of the Windows page file represents the actual limit for extending the extended memory. The profile parameter phys_memsize determines how much of the total main memory is used by the SAP system. The parameter is entered according to the input at installation. The default value for phys_memsize is the size of the main memory (MM).

The memory allocation strategy for a non-dialog work process was changed as of Release 4.0B. Through the previous allocation sequence, the extended memory was protected to the benefit of the heap memory. This is no longer necessary when using the dynamic extended memory, and the allocation sequence of the batch work processes is identical to the sequence of the dialog work processes (see Allocating Memory for User Contexts). Another beneficial side effect is that you can avoid the PRIV mode (see Private Memory) for background work processes and thereby starting the work processes.

Sequence of allocating memory for non-dialog work processes:

...

1. Roll memory until the limit ztta/roll_first

2. Extended memory until the limit min {em/address_space_MB, ztta/roll_extension}

3. Roll memory until the limit ztta/roll_area

4. Heap memory until the limit abap/heap_area_nondia

The basis for zero administration memory management is a sufficiently large Windows page file. The previous recommendation still remains:

Windows page file = 3 to 4 times the main memory size

All relevant memory management parameters are set with an optimal default value so that all manual configurations are unnecessary.

Hope this is useful.

Regards,

Deepak Kori

[nicholas_chang]

Hi,

You can refer to Note 88416 - Zero administration memory management for the ABAP server for more information.

To simplify how ZAMM works in your system, you need to set PHYS_MEMSIZE to reasonable amount of memory based on the physical memory available on your system, with the consideration of memory assign to database, external applications, os and etc.

To maximize the benefits offered by "Zero Administration Memory Management" on Windows, you can delete below parameters from your instance profile:

ztta/roll_first

abap/heaplimit

ztta/roll_extension

abap/heap_area_dia

Cheers,

Nicholas Chang

[Former Member]

Hi,

Zero administrator memory in SAP memory mangement is totally depend on how much ram you want to give to SAP for execution i.e PHY_memory profile parameter. It will control the some of the parameter which are provided fellow SDN members.

Thanks,

Subhash.G