Re: nfs performance problem

["Ragnar Kjørstad" <nfs@ragnark.vestdata.no>]

On Thu, Nov 07, 2002 at 09:19:44AM -0600, Baker, Byran wrote:
> We have a couple of NFS servers with 3ware cards.  One is a 3ware 7850 =
(8
> Maxtor 160GB - 5400RPM) and one is a 3ware 7500-12, both configured wit=
h
> RAID 5 + Hot Spare.  I have all the latest NFS patches applied.  If I a=
ccess
> an NFS mounted directory on one of these systems and copy a bunch of li=
ttle
> files (1-2KB), I get 150-250 tps.  If I access larger files (90% > 1MB =
each)
> I will normally see 25-60MB/s transfer with 500-700 tps, with peaks of =
over
> 1000 tps - A good indication that disk seek is to blame for the problem=
 with
> the small files.


Just to clarify here.

I bet when you transfer 1-2KB files you are able to transfer 150-250
files pr second, right?=20

When you transfer larger files the files pr second rate goes down, but
the tps-rate increases because each file is split into multiple scsi
requests.=20


And yes, I would agree with your conclution that disk seek is to blame.

Are those numbers for reads or writes? I would expect to see the same
tendency, but with stronger effect, for writes than reads.



--=20
Ragnar Kj=F8rstad
Big Storage


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