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Memory Allocation

Work process memory allocation strategy can be different according to different release and platform.

In general, we know the allocation of Dialog and Non-Dialog work process are different.
Dialog -> Roll First -> EM -> Roll Area  -> Heap
Non-Dialog -> Roll Area -> Heap -> EM

AIX - With configuration of  ES/TABLES = SHM_SEGS, the nonDIA allocation strategy is same as DIA.
Windows  and Pase400 -  the allocation order is changed in general
Linux - the order is changed when em/implementation is set to map

Please also refer to note 177226 on report RSMEMORY

Below SAP Help links are useful

( Please note that Memory management issue under Windows platform is typically handled under BC-OP-NT component. )

Resource and Quota are two important terms that we need to understand. Quota limits the usage, which is important to prevent further consumption of resources. Resources can be come from R/3 itself or systems.

Example of Resource:
swap space

Example of Quotas:
ztta/roll_first, ztta/roll_area

Memory Analysis 
There are many common memory dumps, that we can provide standard guidelines in resolving them.

We will talk about more on memory analysis here on next update. 


SAP Important Memory Notes:


  • #146289 :  Parameter Recommendations for 64-Bit SAP Kernel
  • #425207 : SAP memory management, current parameter ranges
  • #153641 : Swap space requirement for R/3 64-bit kernel
  • #548845 : Internal modes uses more than 2 GB
  • #835474 : More than 32 GB extended memory
  • #1147109 : Heap memory shortage

Operating System Specific:


  • #445533 : Lots of extended memory on AIX (64 bit)
  • #789477 : Large extended memory on AIX (64-bit) as of Kernel 6.20
  • #323816 : User limits on AIX
  • #191801 : AIX 64-bit with very large amount of Extended Memory


  • #1112627 :  SAP on HP-UX: Recommendations for swap and pseudo swap
  • #172747   :  HP-UX Operating System kernel parameter recommendations


  • #941735 :  SAP memory management for 64-bit Linux systems
  • #386605 :  SAP Memory Management for Linux (32-bits)
  • #171356 :  SAP software on Linux: Essential information

Sun Solaris

  • #570375 :  SAP on Sun Solaris: Swap Space and Paging


  • #931024 :  FAQ: 64-bit platforms for Windows
  • #88416   :  Zero administration memory management as of 4.0A/ Windows
  • #13347   :  Windows editions and memory support
  • #110172 :  Windows: Transactions with large memory requirements
  • #129813 :  Windows: Problems due to address space fragmentation
  • #546361 :  FAQ: Storage problems on NT/Windows 2000
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1 Comment

  1. Unknown User (qv3vh3r)


     Is this blog discontinued ?