Note 88416 - Zero administration memory management for the ABAP server

Summary

Symptom
Zero administration memory management on Windows
Reason and Prerequisites
The zero administration memory management on Windows 32-bit and 64-bit systems that is described in this note requires no manual settings and adapts itself dynamically to the memory requirements of the users.

For more information about the parameter settings for memory management, taking the 2 or 3 GB virtual memory restriction on Windows 32-bit into account, see the following document:
"Optimizing the Memory Settings for SAP Systems on 32-Bit Windows".
This document is available on SAP Service Marketplace at: http://service.sap.com/msplatforms -> Windows Server
Solution

Zero administration memory management on Windows
Description of functions

1. The basis for zero administration memory management on Windows is the dynamically self-extending extended memory.

The extended memory is initially set to the size of the profile parameter PHYS_MEMSIZE ([PM]).

If more memory is required by the user, the extended memory extends itself in steps of "min(([PM] / 2), 2)" up to the set limit of the profile parameter em/max_size_MB or until the address space in the Windows page file is used up. By setting the standard value for em/max_size_MB to 20000 MB (100000 MB for 64 bit), it is the size of the Windows page file that represents the actual limit for the extension of the extended memory. The profile parameter PHYS_MEMSIZE determines how much of the entire main memory is to be used by the SAP system. The parameter is entered during installation in accordance with the entry. The standard value for PHYS_MEMSIZE is the size of the main memory [RAM].
As of kernel version 7.20, you can specify PHYS_MEMSIZE relative to the size of the main memory as follows:

PHYS_MEMSIZE=20%

Not all SAP versions provide you with the option of setting the maximum memory consumption individually in a dialog box during the installation of the instance. In this case, the parameter is not set and receives the default value (size of the main memory [RAM]).
If you operate several SAP ABAP Server instances on one computer, you must set the parameter PHYS_MEMSIZE in the instance profiles. For detailed information, refer to Note 1518419.

2. Even with zero administration management, the Windows operating system should be configured in such a way that it keeps the file cache to a minimum size. Therefore, make sure that indicator "Maximize Throughput for Network Application" is activated under 'Control Panel' -> 'Network' -> 'Services' -> 'Server' -> 'Properties'. This parameter can be set up to and including Windows Server 2003 only.  This option no longer exists for Windows Server 2008 and higher. The configuration takes place automatically.

On the 64-bit operating systems Windows Server 2003 and Windows Server 2008 (not Windows Server 2008 R2), if you use certain backup software, the Windows file system cache may increase to high values and this may have a negative effect on the performance of the server. For more information, see Note 1416152.

3. The basis for the zero administration memory management is a sufficiently large Windows page file. For detailed information, refer to Note 1518419.

4. All relevant memory management parameters are predefined with an optimal standard value, making all manual configurations unnecessary.


Default values of zero administration memory management up to kernel version 7.20
[RAM] = size of the physical main memory
[PM] = value of the profile parameter PHYS_MEMSIZE (standard value=[RAM])
[US] = factor dependent on [PM] - calculated automatically

|Profile parameter      |Standard 32-bit|Standard 64-bit|Unit      |
|------------------------|---------------|------------------------|
|    em/initial_size_MB  |----    [PM]  |----    [PM]   |Mbyte     |
|---    em/max_size_MB  |---    20000   |--1.5 * [PM]   |Mbyte  |
|   em/address_space_MB  |-----    512  |-----   4096   |Mbyte     |
|----  ztta/roll_first  |-------    1  |-------    1   |Byte      |
|---    ztta/roll_area  |---  2000000  |---  3000000   |Byte      |
|  ztta/roll_extension  |  2000000000  |  2000000000   |Byte      |
|    abap/heap_area_dia  |  2000000000  |           2000000000   |Byte      |
| abap/heap_area_nondia  |  2000000000  |           0  |Byte      |
|  abap/heap_area_total  |  2000000000  |[PM]*1048576   |Byte      |
|-    rdisp/ROLL_MAXFS  |  [US] * 100   |  [US] * 100  |8KB-Block|
|---    rdisp/ROLL_SHM  |  [US] * 100   |  [US] * 100  |8KB-Block|
|---    rdisp/PG_MAXFS  |---    32768  |---    32768   |8KB Block |
|-----    rdisp/PG_SHM  |   [US] * 50  |   [US] * 50  |8KB-Block|
|------------------------|---------------|------------------------|


Default values of zero administration memory management as of kernel version 7.40

[RAM] = size of the physical main memory
[PM] = value of the profile parameter PHYS_MEMSIZE
[EI] = value of the profile parameter em/initial_size_MB

In 7.40, parameter values can contain formulas. The expression $(Param) in the value of a parameter references the value of the parameter with the name Param.

|Profile parameter            |Standard 64-Bit          | Unit |
|----------------------------|-------------------------|---------|
|    PHYS_MEMSIZE            | 1.0 * [RAM]            |MByte....|
|    em/initial_size_MB      | 0.7 *[PM]               |MByte    |
|        em/max_size_MB      | 1.5 * [PM]              |MByte    |
|      abap/buffersize      | [EI]*1024*0.15          |KByte    |
|        abap/programs      | $(abap/buffersize)/4    |Entries  |
|    abap/heap_area_dia      | 2000000000              |Byte     |
| abap/heap_area_nondia      | 0                      |Byte     |
|  abap/heap_area_total      | 1048576 * [PM]          |Byte    |
|abap/shared_objects_size_MB | [EI] * 0.02            |MByte    |
|   em/address_space_MB      | [EI]                    |MByte    |
|        em/max_size_MB      | [PM].*.1.5              |MByte    |
|    rdisp/wp_ca_blk_no      |$(rdisp/elem_per_queue)*3|Entries  |
|          rdisp/PG_SHM      |  max(min(1000+40*max(5,floor((    |
|          $(PHYS_MEMSIZE)-128)*25/128)),16384),1024) |8KB-Block|
|        rdisp/PG_MAXFS      | 32768                  |8KB-Block|
| rsdb/ntab/entrycount       | $(zcsa/db_max_buftab)   |Entries  |
|  rsdb/ntab/ftabsize       | min(500000,                      |
|                            ($(rsdb/ntab/entrycount)))|KByte    |
|    rsts/ccc/cache07       |$(rsts/ccc/cachesize)*0.1|Bytes    |
|  rtbb/buffer_length      |$(zcsa/table_buffer_area)*         |
|                                          0.1 / 1024  |KByte    |
|      rtbb/max_tables      |$(zcsa/db_max_buftab)*0.1|Entries  |
|zcsa/table_buffer_area......| max(30000000,                    |
|          $(em/initial_size_MB) * 1024 * 1024 * 0.05) |Byte     |
|  ztta/roll_extension      | 2000000000              |Byte    |
|----------------------------|-------------------------|---------|

5. In individual cases, customer-specific requirements may demand an individual parameterization. For this, the system usually recommends the different values setting to you after an EarlyWatch Session.
If you want to use the default values that were calculated automatically, you must not list the relevant profile parameter in the instance profile or Default.pfl.
If you want to use transaction RZ10 to delete or deactivate the above mentioned profile parameters, use the "Extended maintenance" function in RZ10. "Basic maintenance" is not suitable for deleting these parameters.

6. Zero administration memory management on Windows intends to reduce the number of relevant profile parameters. As a result, the maintenance and configuration of the application server is simplified, and the available resources are optimally used.

Header Data

Release Status:	Released for Customer
Released on:	13.02.2013  08:15:14
Master Language:	German
Priority:	Recommendations/additional info
Category:	Special development
Primary Component:	BC-OP-NT Windows
Secondary Components:	BC-INS-NT Installation Windows