topic Re: Apps not using Device swap in Operating System - HP-UX

Apps not using Device swap

Binu_2 — Wed, 17 Sep 2008 05:10:57 GMT

Hi all,
The glance is showing 100% swap utlised
But its not using device swap

# swapinfo -tam
Mb Mb Mb PCT START/ Mb
TYPE AVAIL USED FREE USED LIMIT RESERVE PRI NAME
dev 8208 16 8192 0% 0 - 1 /dev/vg00/lvol2
reserve - 8192 -8192
memory 9741 9682 59 99%
total 17949 17890 59 100% - 0 -

Can anyone help me

Thanks
Binu

Re: Apps not using Device swap

Gokul Chandola — Wed, 17 Sep 2008 06:23:41 GMT

Hi,
There is 16 MB device swap utilised.
It mean Device Swap is Using, but it should be much ....

For Your Reference
TYPE AVAIL USED FREE USED LIMIT RESERVE PRI NAME
dev 32000 3812 28188 12% 0 - 1 /dev/vg00/lvol9
reserve - 13409 -13409
memory 7148 1509 5639 21%
total 39148 18730 20418 48% - 0 -

Regards,
Gokul Chandola

Re: Apps not using Device swap

Kenan Erdey — Wed, 17 Sep 2008 06:33:19 GMT

Hi,

your system isn't swapping. Processes allocate as much swap as it will get in memory. in your system it's allocated in pseodo swap(just a trick). if processes are really start swapping device swap will be used.

Kenan.

Re: Apps not using Device swap

Steven E. Protter — Wed, 17 Sep 2008 08:00:32 GMT

Shalom,

Apps don't get to pick and choose with regards to swap.

If the app is not using device swap then swap needs to be reconfigured and is not working on the system level.

I recommend using sam or shm (11.31) to reconfigure swap correctly and reboot.

SEP

Re: Apps not using Device swap

SKR_1 — Wed, 17 Sep 2008 08:10:41 GMT

Yes, you need to recreate this swap. May not be configured properly.

Note: your swap area should be double to the physical memory.

Thanks

SKR

Re: Apps not using Device swap

Venkatesh BL — Wed, 17 Sep 2008 09:42:55 GMT

Yes, it could be that the swap is "reserved" for the processes, but, such a time has not come when the system needs to start moving process pages in and out.

Try monitoring 'vmstat' output. You may start seeing 'Page Outs' happening after a while. This will also reflect in the 'swapinfo' output.

Re: Apps not using Device swap

sreekanthtm — Wed, 17 Sep 2008 10:49:08 GMT

What the application running in ur server.
This can happen with oracle. If an oracle apps or database is running in ur server, it reserve the resources for future usage.

Re: Apps not using Device swap

James R. Ferguson — Wed, 17 Sep 2008 11:07:22 GMT

Hi Binu:

You are not actually swapping (yet) since the 'dev'ice swap space used is 0%.

You have, however, reserved all of your memory for processes. Remember that swap space must be reserved during process instantiation. You have 'swapmem_on' enabling pseudoswap (indicated by the line labeled "memory") and that's good, but you most definitely need to add more device swap and/or more physical memory.

Regards!

...JRF...