topic Re: Kernel parameters in Operating System - HP-UX

Kernel parameters

John McDen — Fri, 29 Mar 2002 20:33:19 GMT

Hello

How do i come to know what is the kernel parameter for rsize and wsize for the mount_nfs commands?

rsize=n Set the read buffer size to n bytes. The default value is set by kernel.

wsize=n Set the write buffer size to n bytes. The default value is set by kernel.

How do I know what is the kernel parameter for rsize and wsize?

Also what is the minmum and max size for the values (rsize and wsize).

Thanks in advance.

John McDen

Re: Kernel parameters

Sanjay_6 — Fri, 29 Mar 2002 20:49:38 GMT

Hi John,

The parameters rsize and wsize ae not tunable in the kernel. You can modify their value on the command line with the mount command,

http://us-support3.external.hp.com/cki/bin/doc.pl/sid=ce9f88b016fbfedc60/screen=ckiDisplayDocument?docId=200000024602723

Hope this helps.

Regds

Re: Kernel parameters

John McDen — Fri, 29 Mar 2002 20:53:37 GMT

Thanks Sanjay

It means that I can max go up to 1024k and a min of 8k ??

Re: Kernel parameters

someone_4 — Fri, 29 Mar 2002 20:54:06 GMT

On that note here is one of my fav links ..

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

Also Sanjay the link you gave is for 10.01. Would it be save to assume that this is all good for 11.0 and up?

Richard

Re: Kernel parameters

S.K. Chan — Fri, 29 Mar 2002 21:00:21 GMT

The rsize and wsize are not tunable. They are defined by the mount command. So you can't actually change it in the kernel likea ny other parameters. If you look at /etc/mnttab it'll tell you what is the value of those parameter on the exsiting mounted FS.
The maximum rsize and wsize size is 32 KB.
A typical example of a mount command that uses this option ..
# mount -orsize=1024,wsize=1024 systemA:/opt/apps /apps

Re: Kernel parameters

John McDen — Fri, 29 Mar 2002 21:02:39 GMT

Sanay

But it is for Diskless client (does is really make a difference?? ) I am not sure.

Is it the same for NFS Ver 3 ?? somebody was telling it's 32K default in NFS Ver 3 I am not sure ???

I am totally confused ??

Re: Kernel parameters

S.K. Chan — Fri, 29 Mar 2002 21:03:01 GMT

32K max means ..
rsize=32768 and wsize=32768

Re: Kernel parameters

John McDen — Fri, 29 Mar 2002 21:45:47 GMT

S. K Chan,

But I put a figure of 65536 and it accepted it.

So it means that I can put any number > than 32768 ??? and it will just accept it??

John

Re: Kernel parameters

Giri Sekar. — Fri, 29 Mar 2002 22:22:46 GMT

Hi

Even if you try to set the rsize and wsize to higher value using mount command the system stes it to 32kb. Check in /etc/mnttab for the size in effect.My question to you. why do you want to change it?

Re: Kernel parameters

S.K. Chan — Fri, 29 Mar 2002 22:52:41 GMT

Yes it'll accept it in the command line but it will not set it. It'll fall back to 32K. Run ..
# mount -v
and you should see that mount point that you've just used 64K is actually set at 32K.