topic Create additional swap ?? in Operating System - HP-UX

Create additional swap ??

Chris Fung — Fri, 11 Jan 2002 04:51:22 GMT

Hi,

When I create an additional device swap through SAM, there is an option called "Swap priority" which is default "0". Can anyone tell me what is the implication for the "Swap priority"? Any relationship to the primary swap?

By the way, can anyone tell me how to create swap space through command line mode?

Thanks

Re: Create additional swap ??

Animesh Chakraborty — Fri, 11 Jan 2002 05:00:08 GMT

hi,
Attach document on swap may help you.

Re: Create additional swap ??

Ravi_8 — Fri, 11 Jan 2002 05:17:17 GMT

Hi,
Swap 0 mean top priority, then comes 1,2....
i.e system looks for the swap which has the priority 0 first, if it is full then goes to swap space of priority 1 then 2 like that.

you can create swap thru command like this.
#lvcreate -C -L size-inMB -n pswap /dev/vgxx
#swapon /dev/vgxx/pswap

Re: Create additional swap ??

Sanjay_6 — Fri, 11 Jan 2002 06:02:22 GMT

Hi Chris,

Take a look at the thread below to learn more about swap,

http://docs.hp.com/cgi-bin/fsearch/framedisplay?top=/hpux/onlinedocs/5965-4641/5965-4641_top.html&con=/hpux/onlinedocs/5965-4641/00/00/12-con.html&toc=/hpux/onlinedocs/5965-4641/00/00/12-toc.html&searchterms=swap%7cpriority&queryid=20020110-220358

http://docs.hp.com/cgi-bin/fsearch/framedisplay?top=/hpux/onlinedocs/B2355-90701/B2355-90701_top.html&con=/hpux/onlinedocs/B2355-90701/00/00/50-con.html&toc=/hpux/onlinedocs/B2355-90701/00/00/50-toc.html&searchterms=swap%7cpriority&queryid=20020110-220358

http://us-support3.external.hp.com/cki/bin/doc.pl/sid=4459fbe11b4d3f3b9b/screen=ckiDisplayDocument?docId=200000053039597

Hope this helps.

Regds

Re: Create additional swap ??

Michael Tully — Fri, 11 Jan 2002 06:36:40 GMT

Hi,

There is a document on your hpux server that
illustrates this very well about swap priority.

It can be found in
/usr/shar/doc/mem_mgt.txt

The following is an extract from it about
swap priority.

You can also get information about swap from the system admin guides.

HTH
-Michael

http://www.docs.hp.com/hpux/onlinedocs/B2355-90742/B2355-90742.html

Swap Space Priorities
=====================

Priorities, ranging from zero to ten, can be set for all devices or file systems. The lower the number, the higher the priority. Thus, a device with a priority of zero is used for swapping before a device of priority one or higher.

Swapping rotates among both devices and file systems of equal priority. Given equal priority, however, devices are swapped to by
the operating system before file systems, because devices make more efficient use of CPU time.

We recommend that you assign the same swapping priority to most swap devices, unless a device is significantly slower than the rest.
Assigning equal priorities limits disk head movement, which improves swapping performance.