SAP Note No. 88416 17.04.2008 Page 1
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Number 88416
Version 21 from 15.02.2007
Status Released for Customer
Set on 15.02.2007
Language EN
Master language DE
Short text Zero administration memory management as of 4.0A/
Windows
Responsible Vladislav Vaintroub
Component BC-OP-NT
Windows NT
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Long text
Symptom
Zero administration memory management on Windows as of SAP Release 4.0A.
Other terms
Reason and Prerequisites
The configuration of the memory management on Windows differs
considerably from that of the memory management on UNIX. Previously,
this often resulted in customer systems that were set up incorrectly and
were therefore inefficient. The zero administration memory management on
Windows that is described in this note requires no manual settings and
adapts itself dynamically to the memory requirements of the users. Even
hardware changes (for example, memory enhancement) are detected and the
parameters set accordingly.
You will see configuration examples at the end of this note.
General information about the parameter settings for Memory Management
in Windows 32 bit is available in 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. An "infinitely"
large memory resource is made available with this method. 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 "[PM] / 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 [HS].
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Even with zero administration management, the Windows 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'.
2. The memory allocation strategy of a batch work process was changed
as of 4.0B. The extended memory was preserved by the previous
allocation sequence for the benefit of the process-specific heap
memory. The dynamic extension of the extended memory renders this
unnecessary, and the allocation sequence of the batch WP is
identical to sequence of the dialog WP. An equally useful side
effect of this new method is the avoidance of PRIV modes in batch
and therefore the expensive restarting of the WP.
- Old batch memory allocation sequence:
a) Roll memory up to the quota "ztta/roll_area"
b) Heap memory up to the quota "abap/heap_area_nondia"
c) Extended memory up to the quota "ztta/roll_extension"
- New batch memory allocation sequence:
a) Roll memory up to the quota "ztta/roll_first"
b) Extended memory up to the quota "em/address_space_MB"
c) Roll memory up to the quota "ztta/roll_area"
d) Heap memory up to the quota "abap/heap_area_nondia"
3. The basis for the zero administration memory management is a
sufficiently large Windows page file. The previous recommendation
[Windows page file] = 3 ... 4 * [HS] is still used for 32-bit
operating systems. For 64-bit systems, you should set the page file
to 20 GB at the start, and you can increase the value later on.
4. All relevant memory management parameters are predefined with an
optimal standard value, making all manual configurations
unnecessary.
[HS] = size of the physical main memory
[PM] = value of the profile parameter PHYS_MEMSIZE (standard
value=[HS])
[BE] = maximum possible number of users (calculated from [PM])
Standard values for zero administration memory management
| Profile parameter |Standard 32-bit|Standard 64-bit|Unit
|
|------------------------|-------------- |--------------
|----------|
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| em/initial_size_MB |---- [PM] |---- [PM] |Mbyte
|
|--- em/max_size_MB |--- 20000 |--- 100000 |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 | [BE] * 100 | [BE] * 100 |8KB Block
|
|--- rdisp/ROLL_SHM | [BE] * 100 | [BE] * 100 |8KB Block
|
|--- rdisp/PG_MAXFS |--- 32768 |--- 32768 |8KB Block
|
|----- rdisp/PG_SHM | [BE] * 50 | [BE] * 50 |8KB Block
|
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.
5. The new 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.
6. Sample configuration:
a) Example: Central instance with 8 GB main memory
The dialog users work on other application servers. The SAP
instance on the database server does not require much memory. For
this reason, most of the physical memory can be used for the
database.
Remove all memory management profile parameters (see the above
table), and set PHYS_MEMSIZE to 1000 (~ 1GB). Configure the
database in such a way that it uses the remaining 7 GB of memory
(if this is supported by the database platform).
b) Example: Central instance with 1 GB main memory
Remove all memory management profile parameters (see the above
table), and set PHYS_MEMSIZE to 700 (= 700 MB).
To provide the database with sufficient resources, we recommend
that you restrict the amount of memory that is used by the SAP
instance. As a rule of thumb, use SAP/DB = 70/30 and set the
parameter PHYS_MEMSIZE to approximately 70% of the installed main
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memory.
c) Example: Application server with one dialog instance (1 GB RAM)
Remove all memory management profile parameters, including
PHYS_MEMSIZE.
As a result, the standard value for PHYS_MEMSIZE is automatically
set to the size of the main memory (1 GB). PHYS_MEMSIZE is
automatically adjusted when the memory is upgraded. Actions on
the part of an SAP administrator are not required.
d) Example: Two dialog instances on one application server (1 GB
RAM)
Remove all memory management profile parameters.
Set PHYS_MEMSIZE specifically for each instance, depending on the
respective constraints (productive or test instance, number of
work processes and so on).
If you (for example) run a dialog instance of a test system and a
productive system on a host with 1GB main memory, a logical
configuration might involve setting PHYS_MEMSIZE to 700 MB in the
instance profile of the productive dialog instance and to 300 MB
in the instance profile of the dialog instance of the test
system.
Repairs in the Code
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Note is release-independent
Further components
BC-INS-NT
Installation Windows NT
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Note attributes
Operating system NT/ALPHA
NT/INTEL
Operating system NT/INTELWIN2000
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Reference to related Notes
Number Short text
____________________________________________________________
1009493 abap/heap_area* Parameter Defaults Changed (64-Bit Windows)
931024 FAQ: 64-bit platforms for Windows
923610 Memory param recommendations for Bank Analyzer 4.2 and 5.0
838866 REC: Memory requirement for logical database too large
745641 Memory-related terminations in Reporting Agent pre-calc.
546361 FAQ: Storage problems on NT/Windows 2000
518835 Core dump with 'SAP Address Space Viewer'
407621 INST: 4.6C SR2 R/3 Inst. on Windows 2000: IBM AS/400
146289 Parameter Recommendations for 64-Bit SAP Kernel
129813 Windows: Problems due to address space fragmentation
110172 Windows: Transactions with large memory requirements
103747 Performance: Parameter recommendations as of Release 4.0
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