on 12-15-2011 3:13 PM
Hi Guys,
I would appreciate your assistance/recommendations with Buffer Tuning
Im experiencing high swapping on Several Buffer as shown Below
Which considerations would you take for adjusting these buffers to optimal Values?
Do you estimate the parameters values by incrementing by 10-20% ? Or is there a better way to determine the best values.
Thanks a lot for your help.
Nametab -->Table Definition
Efficiency HITRATIO % 97
HITS 119.405.209
REQUESTS 123.408.979
DB access quality % 97
DB access 4.006.836
DB access saved 119.399.849
Reorgs 0
Size Allocated KB 9.800
Available KB 8.219
Used KB 8.219
Free KB 0
Free KB 0
Directory entries Available 28.826
Used 28.826
Free 0
Swaps Objects swapped 1.032.168
Frames swapped 0
Resets Total 0
Table definition buffer TTAB
rsdb/ntab/entrycount 28826 Max. number of table definitions buffered
Nametab-->Field Definition
Efficiency HITRATIO % 100
HITS 80.761.920
REQUESTS 81.137.309
DB access quality % 100
DB access 363.063
DB access saved 80.761.378
Reorgs 0
Size Allocated KB 45.515
Available KB 43.263
Used KB 40.109
Free KB 3.154
Directory entries Available 28.826
Used 7.176
Free 21.650
Swaps Objects swapped 355.332
Frames swapped 0
Resets Total 0
rsdb/ntab/ftabsize 43263 kB Size of field description buffer
Program
Efficiency HITRATIO % 100
HITS 385.544.192
REQUESTS 385.922.653
DB access quality % 100
DB access 653.940
DB access saved 565.109.488
Reorgs 0
Size Allocated KB 400.000
Available KB 370.780
Used KB 369.428
Free KB 1.352
Gaps KB 1.303
Directory entries Available 100.000
Used 10.385
Free 89.615
Swaps Objects swapped 206.098
Frames swapped 0
Resets Total 0
Program buffer PXA
abap/buffersize 400000 kB Size of program buffer
abap/pxa shared Program buffer mode
Export/Import
Efficiency HITRATIO % 81
HITS 13.737.920
REQUESTS 16.906.841
DB access quality % 100
DB access 0
DB access saved 0
Reorgs 0
Size Allocated KB 4.096
Available KB 3.375
Used KB 2.757
Free KB 253
Directory entries Available 2.000
Used 1.031
Free 969
Swaps Objects swapped 32.476
Frames swapped 428.617*
Resets Total 0
Export/import buffer EIBUF
rsdb/obj/buffersize 4096 kB Size of export/import buffer
rsdb/obj/max_objects 2000 Max. number of objects in the buffer
rsdb/obj/large_object_size 8192 Bytes Estimation for the size of the largest object
rsdb/obj/mutex_n 0 Number of mutexes in Export/Import buffer
Hi,
What's your current free physical memory?
If you have extra free memory, you can allocate 30% to reduce to the swap. Pay attention either the swap happen on size or object directory. Also, you can increase your abap/buffersize to 80000.
As SAP rule of thumb, total memory usage shouldn't exceed 20% of physical memory for paging.
for eg: if your system has 10GB, paging used shouldn't exceed 2GB.
Cheers,
Nicholas Chang
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Hi Martin,
Just to clarify, there's on one SAP instance running on this machine? any other external application?
2) What's your memory setting in MSSQL DB? fix memory setting?
3) go to ST06, what's the current free memory?
Kindly let me know the above as we can maximize the memory usage to optimize your resources.
Cheers,
Nicholas Chang
Hi Martin,
Since 20GB set to MSSQL DB, you can reserve 3GB for system application, process, backup, external process and etc.
Therefore, you can allocate 27GB to SAP system.
You can allocate 22GB to PHYS_MEMSIZE, abap/buffersize to 1000000 and 30% to SAP buffer in ST02 where you noticed alot of SWAP. Also, you can allocate additional space to rdisp/ROLL_SHM and rdisp/PG_SHM if the percentage of "In Memory used" is around or more than 80%.
You can check based on the history usage in ST02.
However, try not the exceed the shared memory of 27GB for total memory assigned for SAP system, you can check at ST02 -> detailed analysis -> storage.
Cheers,
Nicholas Chang
Hello,
If you don't find any specific Notes for e.g. Note 373986 - Overflow of the export/import buffer and Note 121808 - Swaps in program buffer although space is free, then better to go with 10-20% increment.
Thanks
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