initial_size_MB

[Former Member]

memlimits output

Posted: Apr 21, 2006 8:46 PM Reply

Hi,

When i give memlimits command from the sidadm id, i am getting the following output:

SAP R/3 address space configuration test tool V3.2 (98/01/14)

=========================================================================

Restart, set early swap allocation (PSALLOC=early)

SAP R/3 address space configuration test tool V3.2 (98/01/14)

=========================================================================

Check the maximum data size per process (malloc)

Check the available swap space (malloc in several processes)

Process 1859680 allocating ... Size = 4096MB Total: 4096MB

Upper size limit 4096 reached. Finish checking

Total available swap space = 4096MBCheck the maximum size of mapped file (mmap anonymous,dev/zero)

Check protection operations on this area (protect)

Trying to mmap 512MB ... successfull

Trying to mmap 768MB ... successfull

Trying to mmap 1024MB ... successfull

Trying to mmap 1280MB ... successfull

Trying to mmap 1536MB ... successfull

Trying to mmap 1792MB ... successfull

Trying to mmap 2048MB ... successfull

Trying to mmap 2304MB ... successfull

Trying to mmap 2560MB ... successfull

Trying to mmap 2816MB ... successfull

Trying to mmap 3072MB ... successfull

Trying to mmap 3328MB ... successfull

Trying to mmap 3584MB ... successfull

Trying to mmap 3840MB ... successfull

Trying to mmap 4096MB ... successfull

Upper size limit 4096 reached. Finish checking

Trying to mprotect 4096MB ... successfull

Maximum mapped file size: 4096MB

Maximum mprotect size: 4096MB

R/3 parameter em/initial_size_MB up to 4096 permitted

Check the maximum address space per process usable

both by process local memory and mapped file

Maximum address space ( mmap(4096 MB)+ malloc(1676MB) 😞 5772MB

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Result

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Maximum heap size per process........: 4096 MB

measurement limited to 4096 MB

this value is probably limited by swap space

Maximum mapped file size (mmap)......: 4096 MB

measurement limited to 4096 MB

Maximum protectable size (mprotect)..: 4096 MB

measurement limited to 4096 MB

em/initial_size_MB > 4096 MB will not work

Maximum address space per process....: 5772 MB

Total available swap space...........: 4096 MB

measurement limited to 4096 MB

main memory size x 3 recommended , minimum 1 GB

Check the ones in bold, the swap space in our system is 20GB, the inital size_MB value is 8192 and the blocksize_kb is also 8192. Still the message seems to be like that, what is reason behind this ?

Ours is AIX 64bit and NW04 (R/3 is ECC 5.0)

Thanks

[Former Member]

Hi Aravind S,

Note #332591 (memlimits output irritating) contains related information about memlimits and extended memory. The file dev_disp and ST02 transaction are better indications of the amount of memory being allocated to extended memory.

If as recommended according to note #789477 (Lots of Extended Memory on AIX (64-Bit) as of Kernel 6.20) the parameter ES/TABLE = SHM_SEGS, then em/initial_size_MB is not used to set the total extended memory of that instance but instead EM/TOTAL_SIZE_MB.

Notes #835474 (More than 32GB extended memory) and the note #835474 for older releases contain some more related information about relationship between em/blocksize_KB and em/initial_size_MB (or EM/TOTAL_SIZE_MB).

I hope this helps, after setting parameters according to notes above and #146289 (Parameter Recommendations for 64-Bit SAP Kernel), then you can ignore this return from memlimits.

Regards, Mark