[CentOS] NFS performance - default rsize
Ross Walker
rswwalker at gmail.com
Tue Jun 22 13:35:57 UTC 2010
On Jun 21, 2010, at 12:26 PM, Alex Still <alex.ranskis at gmail.com> wrote:
> On Mon, Jun 21, 2010 at 4:38 PM, Nataraj <incoming-centos at rjl.com> wrote:
>
> [...]
>
>> Well, it's been a long time since I've done troubleshooting on large NFS
>> networks, but here's an idea...
>>
>> Are you seeing any kind of packet loss/retransmissions? Take a look at
>> netstat -s. When I last did this work it was with NFS over udp, but I
>> think retransmitted packets will cause more performance loss with large
>> packet sizes. I used to find machines with broken ethernet interfaces
>> that would cause these kinds of problems.
>>
>> Nataraj
>
>
> Thanks guys for the feedback.
> I've done more tests : There are very very few retransmits (less than
> 0,01%) so I don't think that's what happening.
> The client still seems to be "waiting" for something between requests,
> very strange.
>
> On some servers this behavior returned despite rsize being set to 32k,
> I had to set it to 8k to get reasonnable throughput. So there's
> definitly something fishy going on. This has been reported on over 20
> machines, so I don't think it's faulty hardware we're seeing.
>
> Any thoughts, ideas on how to debug this ?
Can you explain the network environment and the connectivity between the client and server some more.
-Ross
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