E420R with very high kernel activity (how to debug)

From: David Foster (foster@ncmir.ucsd.edu)
Date: Thu Jan 29 2004 - 14:17:45 EST


I have an E420R (rack-mounted Ultra80) system running Solaris 8
at kernel 108528-27, recommended patches installed. This system
is one of our main NFS servers, with an A5100 and a T3+ attached
via fibre.

'top' shows a high amount of "kernel thrashing":

CPU states: 71.6% idle, 0.2% user, 25.5% kernel, 2.7% iowait, 0.0% swap

and NFS clients are getting error messages like:

Jan 29 10:59:41 superman kernel: nfs: server <host> not responding, still trying
Jan 29 10:59:42 superman kernel: nfs: server <host> OK

NFS activity is noticably slow.

Suggestions as to how to debug this would be very welcome. We have a second
NFS server that has similar iowait stats but does not show similar kernel
activity, same OS/kernel/patches. Kernel patch 108528-26 had similar
problems, moving to -27 didn't help.

Dave Foster

  =-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=
   David Foster National Center for Microscopy and Imaging Research
    Programmer/Analyst University of California, San Diego
    dfoster[at]ucsd[dot]edu Department of Neuroscience, Mail 0608
    (858) 534-7968 http://ncmir.ucsd.edu/
  =-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=

   "The reasonable man adapts himself to the world; the unreasonable one
   persists in trying to adapt the world to himself. Therefore, all progress
   depends on the unreasonable." -- George Bernard Shaw
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