topic Re: swapspace in Operating System - HP-UX

swapspace

Khashru — Tue, 26 Jun 2007 20:10:56 GMT

What is the maximum swap space that can be configured in hp-ux.

It is a CSA question.

Re: swapspace

Reshma Malusare — Tue, 26 Jun 2007 20:56:09 GMT

Hi Khashru,

The default maximum amount of swap space you can configure, for both device swap and file system swap combined, is approximately 512MB. The tunable system parameter maxswapchunks controls this maximum.

The parameter maxswapchunks (default value of 256) limits the number of swap space chunks. The default size of each chunk of swap space is 2MB.

For example, when the value of the parameter maxswapchunks is 256, the maximum configurable device swap space (maxswapchunks x swchunk x DEV_BSIZE) is:

Thanks & Regards
Reshma

Re: swapspace

Don Morris_1 — Wed, 27 Jun 2007 09:02:57 GMT

Depends on the release. (The prior answer does apply to 11.0 or 11.11).

More details at:
http://docs.hp.com/en/TKP-90202/re38.html
[11.11 maxswapchunks man page]
but in short, 11.11 with no reconfiguration has a maximum swap space of 512Mb, raising maxswapchunks but not swchunk will get you up to 32Gb, raising both to their maxima gets you a maximum of 1Tb.

For 11.23 (really 11.22 and beyond if I recall correctly), maxswapchunks is gone. The kernel instead adjusts what it sized automatically, so you can effectively consider it to be up to the maximum (since the kernel will do that for you if needed), and the default unconfigured swap maximum is 32Gb, up to 1Tb by reconfiguring swchunk.
See:
http://docs.hp.com/en/B2355-60103/swchunk.5.html

For 11.31, maxswapchunks is still gone, but there's more range. The default value of swchunk allows 4Pb of swap (4096Tb). The absolute maximum (by raising swchunk) would be 128Pb. See:
http://docs.hp.com/en/B2355-60130/swchunk.5.html

[Or on an 11.23 or higher system, just man swchunk -- 11.11 has tunable man pages on the web, later releases shipped with them in Section 5.]

Re: swapspace

Fat Scrape — Wed, 27 Jun 2007 09:21:03 GMT

Hi,

I apply this role:

1,25 the amount of phisical memory
because swap device also serves as a dump area (used by savecore) when no other dump area is specifically designated.

Regards,

Fat

Re: swapspace

Fat Scrape — Wed, 27 Jun 2007 09:23:35 GMT

Hi,

sorry I understand mimimum.

see this doc to designing the size of swap allocation:

http://docs.hp.com/en/B2355-90672/ch06.html

Regards,

Fat

Re: swapspace

karthik_in83 — Thu, 28 Jun 2007 02:52:40 GMT

hi,

default is 512mb...
but we can change the size by edit maxswapchunks=(size)

by KK

Re: swapspace

Srinivas Thokala_1 — Thu, 28 Jun 2007 15:12:39 GMT

The normal rule for defining swap space is at least twice of the physical memory. I think the max parameters are not defined.

-Srinivas