topic Re: virtual memory paging in Operating System - HP-UX

virtual memory paging

prakash singh — Mon, 30 Apr 2007 05:33:13 GMT

hi friend,
i m using database oracle 10G with RAC running on 2 instances on hp ux 11iv2 environment. This given message i m getting on one instance. how can i solve this problem.
"Significant virtual memory paging was detected on the host operating system."

thanx

Re: virtual memory paging

Marco A. — Mon, 30 Apr 2007 06:10:55 GMT

Hello ,

Is that a dedicated server for oracle, or does it has another big process like ISS?

Check your sga_max_size, sga_target, and your pga_aggregate_target that could be giving that error.

Please advice,

Rgds

Re: virtual memory paging

Danny Petterson - DK — Mon, 30 Apr 2007 06:13:31 GMT

Hi!

Try to use top, vmstat, etc. to find what is using all the ressources on the system. Is it an error you have recieved all the time this particular instance has been running?

Greetings
Danny

Re: virtual memory paging

Rita C Workman — Mon, 30 Apr 2007 07:39:06 GMT

How much physical memory do you have onthis box ? It is quite possible, especially with Oracle 10, that you might need to increase it.

Otherwise, follow the advice above, and check what else is eating up the resources on this box.

Rgrds,
Rita

Re: virtual memory paging

gigiz — Mon, 30 Apr 2007 07:45:28 GMT

check yor system performance with:
sar -w
vmstat
swapinfo
glance
then attach your result for analize ti ...

Re: virtual memory paging

Steven E. Protter — Mon, 30 Apr 2007 08:48:24 GMT

Shalom,

Oracle's getting pretty good at detecting these probems.

Use vmstat or http://www.hpux.ws/system.perf.sh to identify the problem.

Then buy some memory or tune oracle SGA to use a lot less memory.

Paging is never a good thing and the only fix is more RAM.

SEP

Re: virtual memory paging

Bill Hassell — Mon, 30 Apr 2007 12:18:39 GMT

The simplest verification is to run vmstat when the system is quite busy. Look at the "po" column (page out). One digit (ie, 0-9) is OK, two digits (10-99) is not too good, and 3 digits or more is horrible. If you are running two instances with 2Gb of RAM, your performance is guaranteed to be pitiful for more than a couple of users. You should have about 4-8Gb per instance, double or triple that value for high performance. But you will likely need additional processors to take advantage of the additional RAM.