topic Re: Ssystem permformance in Operating System - HP-UX

Ssystem permformance

sachit patil — Wed, 17 Sep 2008 04:44:39 GMT

My system have 61440mb ram configured and 4096is pscudo swap and 16384 is device swap configured. but utilizzation of swap is more than 70%. There is SAP application ruuning on this system.

Please let me know the value to whcih the page file can be increased in this system.

Mb Mb Mb PCT START/ Mb
TYPE AVAIL USED FREE USED LIMIT RESERVE PRI NAME
dev 4096 0 4096 0% 0 - 1 /dev/vg00/lvol2
dev 16384 0 16384 0% 0 - 1 /dev/vg00/lvswap1
reserve - 20480 -20480
memory 47920 29390 18530 61%
total 68400 49870 18530 73% - 0 -

Regards
SAchit

Re: Ssystem permformance

Ivan Krastev — Wed, 17 Sep 2008 06:55:32 GMT

See this old thread how to add swap - http://forums11.itrc.hp.com/service/forums/questionanswer.do?threadId=451429

regards,
ivan

Re: Ssystem permformance

SKR_1 — Wed, 17 Sep 2008 08:06:16 GMT

Hi Sachit,

You have physical memory about 48 GB and your device swap is only 16 GB. You need to make it double of the physical memory.

lvcreate -L size -n swap1 /dev/vg00
swapon -p 0 lvolname

Thanks
SKR

Re: Ssystem permformance

Steven E. Protter — Wed, 17 Sep 2008 09:09:06 GMT

Shalom Sachit,

Rarely to I respond directly to others posts:

You have physical memory about 48 GB and your device swap is only 16 GB. You need to make it double of the physical memory.

Absolutely not true. It is a rule that applied to small systems with very limited RAM.

On a system with this much ram you do not need device swap to be twice ram. You can get away with 1 times ram easily.

You are not using any swap at all at this point.

Check that swap is properly enabled, because that is the real source of this issue.

SEP

Re: Ssystem permformance

Hein van den Heuvel — Wed, 17 Sep 2008 12:38:56 GMT

The subject reads 'system performance'

Please help me understand how the subject is supposed to relate to the stated question.

Why you do you feel you need to increase the swapfile... it is not being used according to the details provided

And what does that have to do with system performance?

More swap doesn't make a system faster, if not used. It does make it 'survive' though when the pressure is high.

Is the performance good or bad?

If it is bad, that what have you done to determine the underlying reasong for the slowness, typically a resource shortage like PHYSICAL (not swap) memory, CPU or IO capacity being exceeded?

System tools like GLANCE, SAR, VMSTAT may help, have you already used the SAP performance monitorring transactions like ST06 (system, detail analysis for disk performance)), ST02 (sap memory use), ST04 (database)...

What problem are you really tryign to solve?

Regards,
Hein van den Heuvel
HvdH Performance Consulting