Poor PE4600 NFS performance

Aly Dharshi aly.dharshi at uleth.ca
Mon Aug 5 19:17:01 CDT 2002


Hello,

Rick Gaudette wrote:
> 
> It is the onboard broadcom chip.
> 

	I am going to venture a personal opinion, I think that Broadcom cards aren't the 
best, Intel is better in performance, I wonder if that has anything to do with 
it. I guess its worth an expensive experiment to try another card maybe a Intel 
or 3Com gig card ??? :) :) :)

> 
> 
> Would this still apply if there are typically only one or two users
> reading at any given time?  Our typical use model is that one or two
> users might be trying to read a 1-2 GB data file at any given time. 
> That is the type of use model we wish to get the best performance for.

	I don't think this would do much in terms of 1-2 users at a go, unless you are 
planning on servicing a Computer Science network with 120 Unix workstations and 
whole bunch of students. I would consider maybe putting in another gig nic if 
you are reading this amount at a go. Later maybe ??

> 
> Anyone have any recommendations here?  We have tried a bunch but the
> default seems to work best.  The man pages say the default is 8K but
> when we specify 8K we get degraded performance.  The defaults seem to
> perform the same as 32K.
> 

	I seem to stick to nfs settings in the man pages, the default is 1024bytes. They 
seem to claim that thru' put is greatly improved with rsize=wsize=8192bytes. So 
I am surprised that you are having a bad performance.


> 
> UDP.  I would like to try to use TCP but as far as I can tell the RH
> kernels don't support it.  Anyone know how to enable TCP based NFS on RH
> kernels.

	Man nfs says that if you add tcp to the end of the options then it will start up 
as a tcp nfs system as opposed to udp, RH ???. Again subject to experimenting 
adding that at the end of the /etc/fstab line that I provided maybe adding tcp 
may do the trick. Most of the Linux NFS is v2 maybe toggling it to version 3 may 
provide more improvement ??? (Pure experimentation !)

> 
> A bit more info that I have noticed.  nfsstat reports that the number of
> retries is pretty significant compared the number of calls.  The clients
> all say that there is 1 retrans for every 3 calls to the PE 4600.  This
> doesn't sound good to me but I am not sure how to fix it.
> 

	My system seems to provide more information for V3 NFS as opposed to that of V2. 
I guess V3 maybe the defaults ?

	HTH.

	Cheers,

	Aly.


-- 
Aly Dharshi
aly.dharshi at uleth.ca
System Administrator ORS Servers
University of Lethbridge

	"A good speech is like a good dress
	that's short enough to be interesting
	and long enough to cover the subject"




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