topic Re: increasing device swap in Operating System - HP-UX

increasing device swap

akarayil — Thu, 17 Jul 2008 08:29:45 GMT

Hi experts,
we have a rx4640(hp 11.23)with 16GB memory. Two swap LVs, with 4GB each(total 8GB), are configured in the same PV(I know that this is not recommended). I've a 73GB free disk.
I want to increase the swap using space from the other disk.
my question is, should I extend the vg00 using the free disk and create LV for swap(I feel this is better) or create new LV for swap on new VG?
size should be 4GB or 8GB?
As the size of primary swap is 4GB, I think the same size is better.
Can you give me the best option?

with thanks and regards,

Re: increasing device swap

Kenan Erdey — Thu, 17 Jul 2008 08:47:51 GMT

hi,

try this link:

http://forums11.itrc.hp.com/service/forums/questionanswer.do?threadId=962784

and if you have pseudo swap you may not need much swap area.

Kenan.

Re: increasing device swap

Venkatesh BL — Thu, 17 Jul 2008 08:52:23 GMT

> As the size of primary swap is 4GB, I think the same size is better.

They don't need to be of same size, as they are not related to each other as such. During low memory condition, the paging routine would use up the primary swap device and then go to the secondary swap device.

Re: increasing device swap

akarayil — Fri, 18 Jul 2008 05:24:18 GMT

On 17th night, one critical system process was terminated because of shortage of memory. Thats why I tried to increase the swap. But the problem was solved by changing dbc_max_pct kernal parameter value from 50 to 15.

Thank you for all your valuable suggestions

Re: increasing device swap

Dennis Handly — Fri, 18 Jul 2008 07:06:26 GMT

>But the problem was solved by changing dbc_max_pct kernel parameter value from 50 to 15.

It still might be useful for you to provide your "swapinfo -tam" output.

Re: increasing device swap

akarayil — Fri, 18 Jul 2008 08:02:32 GMT

Hi,

> It still might be useful for you to provide >your "swapinfo -tam" output.

#swapinfo -tam
Mb Mb Mb PCT START/ Mb
TYPE AVAIL USED FREE USED LIMIT RESERVE PRI NAME
dev 4096 8 4088 0% 0 - 1 /dev/vg00/lvol2
dev 4096 8 4088 0% 0 - 1 /dev/vg00/lvol9
reserve - 5314 -5314
memory 18420 3824 14596 21%
total 26612 9154 17458 34% - 0 -

regards

Re: increasing device swap

Dennis Handly — Fri, 18 Jul 2008 09:10:40 GMT

>total 26612 9154 17458 34% - 0 -

Now you have only 34% used. If you expect to add a lot more activity on the system, you may need more swap.

Re: increasing device swap

akarayil — Thu, 24 Jul 2008 03:42:04 GMT

Hi,
Once again I faced the same problem.To prevent the process from being terminated, I think, I should increase the swap.
So, for better performance, What swap size should I enable on other disk?

Regards,

Re: increasing device swap

Venkatesh BL — Thu, 24 Jul 2008 04:12:12 GMT

Try to add single largest free disk as additional swap.