nfs performance of 2800.

sean finney sean at stickybit.se
Wed Jan 10 16:25:41 CST 2007


hi ian,

On Wed, 2007-01-10 at 13:42 +1000, Ian Mortimer wrote:
> I've been testing nfs performance of a 2800 (RHEL4 x86_64, PERC 4e/Di,
> Raid 5).  One simple test (bash loop appending lines to a text file)
> gets these timings:
> 
>    to 2800 over nfs:                     20.072s
> 
>    to old file server over nfs:           4.437s
> 
>    on 2800 to local disk:                 0.438s
> 
>    on old file server to local disk:      0.464s
> 
> (Old file server is 32 bit, 2.4 series kernel)
> 
> The surprising result is the far worse nfs performance of the 2800
> compared to the old file server.   Experimenting with mount options
> (rsize, wsize) makes no difference.  nfsvers=2 makes it much worse!

what ethernet chip comes on the 2800's?  is it using hardware-enabled
TSO?  i had to debug some horrible nfs performance a couple weeks back
which could be traced back to the fact that TSO was turned on.  turning
it off and the bottlneck went away.  you can see the settings with

	ethtool -k devname

and set it with

	ethtool -K devname tso off

worth a shot anyway, if nothing else works.


	sean
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