nfs performance of 2800.

Jonathan Dill jonathan at nerds.net
Wed Jan 10 00:12:55 CST 2007


Ian Mortimer wrote:
> I've tested from more than one client.  Some of these are into the
> same switch as the 2800, some into the same switch as the old file
> server.  The results don't vary much and in all cases the old file
> server is much faster on this particular test (and only this test).
>
> On all other tests the new file server is faster than the old which
> seems to rule out network issues.
>   
Not necessarily, the characteristics of the particular "slow" test could 
be very different from a network perspective, may be smaller packets but 
lots of them, that should show up in wireshark.

One thing that has changed not too long ago is that "sync" is now the 
default option for NFS mount instead of "async", you might try 
explicitly using one or the other and see if that makes a difference.

What version of Linux is on the "old" server, saw it's 32bit w/ 2.4 
kernel but not what distro and version number.
>> try a smaller wsize / rsize (1024 / 512) and see what happens
>> try TCP vs. UDP
>>     
>
> Either of these makes performance slightly worse (on this test).
>   
Guessing it's not a packet fragmentation / MTU issue then, but you could 
be hitting switching performance of the switch with a high volume of 
frames albeit smaller ones.
> I'm wondering if it's due to changes in nfs between 2.4 and 2.6 kernels
> (but I don't have any easy way to test that).
>   
See if you can boot the 2800 from a Live CD with 32bit / 2.4 kernel then 
see what happens, you'll want to mount a partition and export that and 
not the CD of course.  I'd try Knoppix for 32bit then Knoppix64, 
alternatively Ubuntu or Centos, not sure you are going to find x86_64 
with 2.4 kernel and necessary drivers for the hardware.  It seems to me 
someone had a Debian Sarge ISO for PE1850 with 2.4 kernel / 32bit that 
might work.

Jonathan



More information about the Linux-PowerEdge mailing list