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