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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