Re: Weird NFS problems

From: Skylar Thompson (skylar_at_cs.earlham.edu)
Date: 05/31/05

  • Next message: Danny Cooper: "RE: DELL PowerEdge 2850 and FreeBSD 5.4"
    Date: Tue, 31 May 2005 10:44:58 -0500
    To: Jon Dama <jd@ugcs.caltech.edu>
    
    
    

    Jon Dama wrote:

    >Try switching to TCP NFS.
    >
    >a 100MBit interface cannot keep up with a 1GBit interface in a bridge
    >configuration. Therefore, in the long run, at full-bore you'd expect to
    >drop 9 out of every 10 ethernet frames.
    >
    >MTU is 1500 therefore 1K works (it fits in one frame), 2K doesn't (your
    >NFS transactions are split across frames, one of which will almost
    >certainly be dropped, it's UDP so the loss of one frame invalidates the
    >whole transaction).
    >
    >This is the same reason you can't use UDP with a block size greater than
    >MTU to use NFS over your DSL or some such arrangement.
    >
    >Incidentially, this has nothing to do with FreeBSD. So if using TCP
    >mounts solves your problem, don't expect Solaris NFS to magically make the
    >UDP case work...
    >
    >

    The thing is that UDP NFS has been working for us for years. A big part
    of our work is performance analysis, so to change our network
    architecture will invalidate a large part of our data.

    -- 
    -- Skylar Thompson (skylar@cs.earlham.edu)
    -- http://www.cs.earlham.edu/~skylar/
    
    



  • Next message: Danny Cooper: "RE: DELL PowerEdge 2850 and FreeBSD 5.4"

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