topic Re: Kernel Parms - maxswapchunks ?? in Operating System - HP-UX

Kernel Parms - maxswapchunks ??

Scott Adams — Wed, 24 Jan 2001 15:57:11 GMT

K210 ; HPUX 10.20

I created a swap area with a size of 1024.
Currect kernel parameters are:
maxswapchunks 512
swchunk 2048
DEV_BSIZE ???

Q1: How do I find the value of DEV_BSIZE?
Q2: What size should maxswapchucks be?

Re: Kernel Parms - maxswapchunks ??

James R. Ferguson — Wed, 24 Jan 2001 16:06:16 GMT

Scott:

DEV_BSIZE is fixed at 1024 and is not configurable.

'swchunk' defaults to 2048 and generally should not be changed. swchunk' defines the "chunk" size, or minimum unit involved in swap activity. Thus, 'swchunk' is the smallest unit of allocation of device or filesystem swap.

'maxswapchunks' defines the maximum number of chunks of swap space allowed on the system.

Thus, the maxiumum number of bytes of swapspace is given by:

bytes of swap = maxswapchunks * swchunk * DEV_BSIZE

...JRF...

Re: Kernel Parms - maxswapchunks ??

Dan Hetzel — Wed, 24 Jan 2001 16:12:22 GMT

Hi Scott,

As your swap space is 1024K
and swapchunks is defined as 2048, a maxswapchunks value of 512 is enough to access all your swap space as 512*2K=1024K.
If you're planning to add more swap in the future, you could increase maxswapchunks to 2048 as this would allow for 4Gb swap.

Best regards,

Dan

Re: Kernel Parms - maxswapchunks ??

koundi — Thu, 25 Jan 2001 09:25:56 GMT

Hi,

Formul to calculate the size of maxswapchunks :
(max swap space in bytes)=maxswapchunksXswchunckXDEV_BSIZE
DEV_BSIZE is fixed at 1024

Regards

HK

Re: Kernel Parms - maxswapchunks ??

federico_3 — Thu, 25 Jan 2001 10:21:11 GMT

In the site below you'll get all the informations about the kernel parameters :

http://docs.hp.com/hpux/onlinedocs/os/KCparams.OverviewAll.html

I hope this helps
Federico