I noticed when transferring files from the new Core2Quad to the fileserver that there seems to be a big burst of file transfer (like 500Mb in a couple of seconds) and then the remaining 200Mb or whatever seems to take forever – so much so that the windows grey out and Nautilus becomes unresponsive. I’ve got a feeling that this is a Compiz or Fedora9 issue, as it doesn’t present itself with Fedora7 – well some unresponsiveness maybe, but that’s probably due to the not-that-great drives or SATA controller in the fileserver. Hell it could be that the Quad is so much faster than the fileserver that it is waiting for it to catchup!
Anyway I’ve been playing around with NFS settings and have set the async bit in /etc/exports, which seems to give a few percent performance increase (copying a 700Mb file takes 50-ish seconds instead of ~1m5s with sync set). None of the /etc/fstab rsize or wsize settings made any difference. I guess that’s still not bad as it works out at 112Mbps – which includes the write time for a 700Mb file, not just the network speed.
I also tried enabling jumbo frames again on my ethernet cards – well that didn’t work, so I tried a piece of crossover cable in case it was my switches or routing setup, but that made no difference. I even tried using the Intel e1000 card with 9k frames instead of the Realtek r8169 cards with 7k frames – still no go. So I’ve come to the conclusion that MTU>1500 just doesn’t work on Linux 2.6 kernels!