Performance Tuning for swap info

[Lee Higginbotham]

We are currently running HP-UX 11
We are having major issues with swap space. We currently have 1 GB of RAM and have 4 GB on order but not due to arrive until 20 JUN.
We have recently migrated to Oracle 9i and I believe this is part of the problem. However our DBA ensures me that he has tuned Oracle down to using the least possible to maintain operations.

Is there any tuning that I can do to make the swap space more available than fuser'ing users after a certain period of idle time?

HELP

Lee Higginbotham

[RAC_1]

What does swpinfo -mat say??
How is buffer cache configured?? dynamic or static??
If dynamic, what are settings for
dbc_max_pct and dbc_min_pct

Anil

[Lee Higginbotham]

Swapinfo -mat produces:

ngbflh:H-SuperUser> swapinfo -mat
Mb Mb Mb PCT START/ Mb
TYPE AVAIL USED FREE USED LIMIT RESERVE PRI NAME
dev 1024 297 727 29% 0 - 1 /dev/vg00/lvol2
reserve - 727 -727
memory 1577 1324 253 84%
total 2601 2348 253 90% - 0 -
You have mail in /var/mail/root
ngbflh:H-SuperUser>

Buffer cache:

bufcache_hash_locks 128 128 Static N/A B
bufpages 7812 7812 Static N/A N

Thanks,

Lee

[Steven E. Protter · Accepted solution]

You are currently swapping.

Based on your swapinfo I predict that though swap will be reserved, paging will stop.

You probably want overall swap space to equal physical memory right after the memory installation. After that you'll need to see if what is being used to plan any further expansion.

Swap space is made available by killing the process its reserved for. If you issue a kill on user processes after idle time, those processes will free up memory and swap.

Oracle processes probably are not idle however, which is why the database itself does not time them out.

The place to look for timeout is probably the application.

I doubt the access is telnet/ssh in which case the TMOUT variable would time out idle users, kill the process and free resources.

In the short run, user education to log off and close the application may be best.

SEP

[A. Clay Stephenson]

Your only real option is to reduce the load until your memory arrives. If you are doing any significant swapping (and you appear to be) the performance impact is so severe that worrying about swap layout is pointless. Your buffer cache is only about 30MB and that is too small to handle the non-Oracle i/o. This was simply a case of not having enough resources to run the application even marginally well. If you are willing to tolerate terrible performance for the sake of more users/applications then you can certainly add more device swap space. You are not limited by the amount of physical memory but rather by the amount of virtual memory BUT you will pay at least a 100X performance hit when you begin to pageout to a significant degree.

[Lee Higginbotham]

Thanks to all that responded. This is what I was fearing. I will get on the vendor to get the memory here ASAP so that should help the issue. I will then get more into the performance tuning.

Thank you again. I have posted the points for each of your responses. I appreciate all of your help and your timely responses.

Lee

[Lee Higginbotham]

Thanks again to all. I'm awating the RAM.