I would try with straight ip to rule out dns, then check io on both server and client as well. On Aug 3, 2011 9:26 PM, "Matt Simmons" <[email protected]> wrote: > Not that it may help in this particular circumstance, but whenever I find > that I have a bizarre problem that can't be easily lumped onto some other > subsystem, I usually suspect DNS. > > On Wed, Aug 3, 2011 at 10:47 PM, Patrick Cable <[email protected]> wrote: > >> I swear, not all my questions are NFS related. Just the weirdest ones. >> >> I have a VxWorks client that connects to a RHEL5 NFS server over UDP. >> The VxWorks device needs to copy a 6MB file into RAM to make something >> happen. >> >> Anyways: connecting to the RHEL5 NFS server over TCP from another >> Linux machine, this file transfer takes a few seconds. Sadly, UDP is >> my only option because that's what was implemented in the kernel. Over >> UDP (both from the VxWorks client and a linux client mounting with >> just '-o udp'), I see unpredictable results: >> >> - Sometimes it will take a few seconds. >> - Sometimes it will take 5ish minutes. >> >> I tried setting the rsize/wsize on the Linux machine to slightly less >> than the MTU (<1500) and things worked at a reasonable rate again, >> consistently. Sadly, VxWorks has no facility to set rsize/wsize; the >> socket buffer is coded in the kernel at 10000 bytes. >> >> When things are acting slow, tcpdump on the RHEL5 NFS server shows >> bursty traffic being sent - chunks of packets being sent, then a few >> seconds pause, then some more chunks, then pause. When thing are >> acting fast, those seconds pause are no longer seconds of pause. >> >> Is there a server side setting I'm overlooking? Lots of googling says >> no, but maybe you have seen something I have not. >> Is there a network congestion thing I'm not taking into account? Not >> entirely impossible -- I don't have any visibility into the switches >> I'm using. The network team says they're not doing any prioritization >> of udp over tcp, which I would not expect or believe but I figured was >> worth asking. >> >> What else should I look at? Because, I'm lost. >> >> A million thanks in advance... >> >> - Pat >> _______________________________________________ >> Tech mailing list >> [email protected] >> https://lists.lopsa.org/cgi-bin/mailman/listinfo/tech >> This list provided by the League of Professional System Administrators >> http://lopsa.org/ >> > > > > -- > LITTLE GIRL: But which cookie will you eat FIRST? > COOKIE MONSTER: Me think you have misconception of cookie-eating process.
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