on 02-03-2015 12:21 PM
Hello All,
In one of our production system, Paging usage is high eventhough physical free ram is available.
We have checked and found that we are not getting any memory dump (like PXA_NO_FREE_SPACE) in the
system.
But we found paging usage is more eventhough there is no activity happened in the system and more physical RAM is avaliable
AIX team confirmed that everything is fine from their end.
Could you please let us know whether we can set rdisp/wp_auto_restart to 86400 S. Also let us know if there is any drawback / dependency need to be checked by setting this parameter.
Also please confirm if there is any paging parameter need to be reduced to resolve this issue
Enviornemnt
AIX 6.1
SAP ECC6.0
Oracle 11.2.0.3.10
Toa
ST02
OS level
Current Value of SAP Parameter
Paging parameters.
-----------------
ipc/shm_psize_10 - 1472000000
rdisp/PG_MAXFS - 800000
rdisp/PG_SHM - 625000
rdisp/ROLL_SHM - 75000
ipc/shm_psize_40 - 562000000
EM/TOTAL_SIZE_MB - 31000
rdisp/wp_max_no - 115
rsdb/obj/buffersize - 1000000
rsdb/obj/max_objects - 250000
abap/buffersize - 3000000
abap/heap_area_dia - 4000000000
abap/heap_area_nondia - 4000000000
abap/heap_area_total - 8000000000
rdisp/accept_remote_trace_level - 0
rsdb/ntab/entrycount - 200000
rsdb/ntab/ftabsize - 240000
rtbb/buffer_length - 180000
rtbb/max_tables - 1500
zcsa/db_max_buftab - 42000
zcsa/table_buffer_area - 810000000
ztta/roll_area - 6500000
gw/accept_remote_trace_level - 1
Regards
Subbu
Hi ,
Your Export/Import Buffer seems to be low and could be increased by another 50% . You may increase your program buffer too ( if its development )
Please check the following note
1971776 - High Usage of Paging Space on AIX
902952 - AIX: Paging even though sufficient free memory
Also bring the following note to the AIX teams notice
1972803 - SAP on AIX: Recommendations
Thanks ,
Manu
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Hello Samb,
This note describes and proposes solution for your problem:
-78498 - High paging rate on AIX servers, in particular DB servers
Also you would check once more your settings per AIX-SAP note:
-1972803 - SAP on AIX: Recommendations
Section 4f
4f) Unexplainable usage of paging space
Sometimes an only slight overcommitment of physical memory, which should lead to only few percent of paging space usage, does lead to a seemingly quite high and long time increasing allocation of paging space. That can often be explained by an AIX optimization feature, keeping lot of "duplicate pages" in paging space, which is discussed in detail in Note 1971776.
Best Regards,
Serhat
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Hi subu,
The Parameter is used to restart the workprocess automatically. And this helps when there is large amount of Paging and work process do not release memory even after restart or cancel with core scenarios.
With the help of this parameter one can regain the memory and bring its utilization to normal.
Which avoids the instance restarts. Also refer to below notes which might help you to understand tha parameter
586824 - Restart SAP work processes for BW
922007 - Changing the parameter rdisp/wp_auto_restart dynamically
And do refer to Serhat recommendations for the parameters.
Let us know if this helps.
Regards,
Ram
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