topic Re: File system swap in Operating System - HP-UX

File system swap

Rumen Ginev — Mon, 02 Dec 2002 09:54:38 GMT

Hi,

I created file system paging area:

# swapon -m 1000M -l 2000M -t fs /dir

swapon made "/dir/paging" directory and 500 files 2 MB each in it, i.e. there were 1GB space initialized.

I expected to see in swapinfo's output additiopnal 1 GB swap space available. Instead, there is only ~150MB under available column. (see the attacment and please, don't comment swap configuration. I have inherited it and I am going to change it soon.)

Where is the problem?

Thanks,
Rumen

Re: File system swap

Stefan Farrelly — Mon, 02 Dec 2002 10:24:56 GMT

I believe you need the -r (reserve) option in order for all the space to show in swapinfo immediately. By creating 1-2Gb of file swap it firstly needs to create the files to that size (as youve seen) but it will only make available whats specified in the -r option which you didnt use.

As a side issue your swap usage is fine - youve tons of unused device swap, you dont need file swap at all. I would remove it at next reboot.

Re: File system swap

Dietmar Konermann — Mon, 02 Dec 2002 13:56:00 GMT

Hmm... IMHO the -r option is to _prevent_ the space from being used for paging. It reserves the space for regular filesystem usage.

Other interesting questions: What OS revision? What swapinfo(1M) patch level?

What is the value of maxswapchunks?

Stefan, the additional swap may not be completely useless here... there are already 7588356 K reserved!

Best regards...
Dietmar.

Re: File system swap

Rumen Ginev — Tue, 03 Dec 2002 07:35:54 GMT

Hi Dietmar,

The OS is HP-UX 11.00, 64-bit
maxswapchunks is 16384, which means 32GB max configurable swap space.

How to check swapinfo(1m) patch level?

Stefan, I had to create additional swap, because of following: We have oracle running in "Dedicated Server" mode. In some situations there are lot of oracle server processes, which resrerve all the available swap. And therefore new processes (NOT only oracle) could not be started.

Regards,
Rumen

Re: File system swap

Dietmar Konermann — Thu, 05 Dec 2002 11:20:55 GMT

Hi!

Hmm... so the maxswapchunks setting is OK.

For the swapinfo patch:

# swlist -l product | grep -i swapinfo

or

# what /usr/sbin/swapinfo

Best regards...
Dietmar.