topic Re: memory leak script in Operating System - HP-UX

memory leak script

Ragni Singh — Tue, 06 Aug 2002 14:41:59 GMT

Hello everyone,

does anyone here have a script that reports on memory leak that they would lilke to share with. Any help will be greatly appreciated.

Re: memory leak script

Stefan Farrelly — Tue, 06 Aug 2002 14:51:47 GMT

I doubt very much there is a script which will do this for you. You have to be a bit more precise in order to find a memory leak. The method I use is;

1. reboot your server but do not start any apps (eg. Oracle)
2. use vmstat to get free memory total.
3. start apps.
4. use vmstat to get free memory total.
5. shutdown apps.
6. same as 4. Now - the free memory total should go back to what is was in 2. before the apps were started. If it doesnt you have a memory leak.
7. repeat for users - check free mem using vmstat, let users on, get users off, does free memory return to previous level ? if not you have a leak.

Re: memory leak script

Bill McNAMARA_1 — Tue, 06 Aug 2002 14:52:44 GMT

Best way is via a small c program that does lots of mallocs and no frees in a loop!

Glance/top to watch Stack size increase..

Later,
Bill

Re: memory leak script

S.K. Chan — Tue, 06 Aug 2002 14:54:06 GMT

Another approach (if you have glance) is to make use of glance's adviser syntax file (proc_mem_leak) to get your numbers.
# cd /opt/perf/examples
# glance -adviser_only -syntax ./proc_mem_leak -j30
==> Samples every 30secs.

You can easily modify "proc_mem_leak" to capture a wide scope of data. For exmaple by default the VSS is set to 30MB. You can change that setting and you'll get more data out of the glance output.

Re: memory leak script

Stefan Farrelly — Tue, 06 Aug 2002 15:17:17 GMT

In the previous reply the glance memory leak file is in this dir, cd here first;

/opt/perf/examples/adviser

Re: memory leak script

Stefan Farrelly — Tue, 06 Aug 2002 15:19:38 GMT

Ive been running that glance adviser on some of our production servers and Im afraid it isnt very good, it only shows processes with VSS > 30Mb !

Re: memory leak script

S.K. Chan — Tue, 06 Aug 2002 15:24:14 GMT

Thanks for the correction Stefan. You can actually modify the file "proc_mem_leak" and change the default value of VSSthreshold from 30000 to a lower value. It does not have to be at 30MB.

Re: memory leak script

Eileen Millen — Tue, 06 Aug 2002 15:33:53 GMT

Hi Sanman,

You can use this command to find out how much memory is being used after booting up.
UNIX95= ps -e -o vsz=Kbytes -o pid,args=Command-Line | sort -rnk1
It is all one line.
Then try it again later to find out what is using the most memory.

Eileen