Memory Allocation and Analysis

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

• Memory Management under UNIX
• Memory Management Under Linux
• Memory Management under Windows
• Memory Management on iSeries

( 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:
em/initial_size_MB
abap/heap_area_total
swap space

Example of Quotas:
ztta/roll_first, ztta/roll_area
ztta/roll_extension
abap/heap_area_(non)dia

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

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

SAP Important Memory Notes:

General: 

• #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:

AIX

• #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

HPUX

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

Linux

• #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

Windows

• #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