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How to detect memory leak

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Kurz
Frequent Advisor

How to detect memory leak

Hi all,

I think we have a memory leak on our SAP DB server. vhand was sometimes as high as 40%, we rebooted, and now it is rising again.

How can I found out which process is consuming the memory?

I attach top and vmstat output. How can I find out more?

best regards,

Michaela
6 REPLIES
Suraj K Sankari
Honored Contributor

Re: How to detect memory leak

Hi,

>>How can I found out which process is consuming the memory?

oracleC11 is taking more memory see one process is taking 8627M

#ps -aef | grep oracleC11
#ps -aef | grep oracleC11 | wc -l

Your most of the memory is taking by Oracle

I think you need to tune your oracle

Suraj
Kurz
Frequent Advisor

Re: How to detect memory leak

Oracle is using shared memory segments, that why the memory consumption appears strange. I.e: It's always the same memory.

best regards,

Michaela
Jitesh purohit_1
Regular Advisor

Re: How to detect memory leak

Hi Michaela ,

The above output does not always shows you have a memory leak on your server..

There are many tools like kmeminfo ( HP ), which can clearly tell if there is a memory leak . So i would suggest you either download & install this tool or log a case with HP Vendor

Analyzing memory performance / Memory leak issues takes lot of understanding of how memory management in HPUX

Thanks
Jitesh
Michal Kapalka (mikap)
Honored Contributor

Re: How to detect memory leak

hi Michaela ,

check the glance or gpm ( gui ) monitoring tool, if you have some bootleneck, a warning message will be generated in other window.

export display where you have X-server and them run gpm.

mikap
Steven E. Protter
Exalted Contributor

Re: How to detect memory leak

Shalom,

Use my handy, dandy memory leak detector.

http://www.hpux.ws/?p=8

Works in Solaris, Linux, HP-UX

SEP
Steven E Protter
Owner of ISN Corporation
http://isnamerica.com
http://hpuxconsulting.com
Sponsor: http://hpux.ws
Twitter: http://twitter.com/hpuxlinux
Founder http://newdatacloud.com
Duncan Edmonstone
Honored Contributor
Solution

Re: How to detect memory leak

Michaela,

Large amounts of activity from vhand in 11iv3 do not necessarily mean you have memory pressure. In 11iv3 vhand is also responsible for freeing pages in the file cache. Have a look at the white paper here:

http://h71028.www7.hp.com/ERC/downloads/4AA0-7157ENW.pdf

And Don Morris's comments in this thread:

http://forums11.itrc.hp.com/service/forums/questionanswer.do?threadId=1241686

So first things first, make sure you are up-to-date on any VM subsystem patches for 11iv3

From what we see here you aren't getting any VM page-outs, so the chances are the vhand activity is associated with the file cache. As this appears to be an Oracle/SAP system, you should probably ensure that all your Oracle filesystems don't use filecache by setting "minacache=direct,convosync=direct" on your VxFS filesystem mount options (I'm assuming here that you have Online JFS). That might stop the apparent cache thrashing (if thats what's happening and its only a guess based on data provided).

HTH

Duncan

HTH

Duncan