mounted machine down => df hangs

[Kenneth A Edwards]

In article <2652 at brazos.Rice.edu> rush at xanadu.llnl.gov (Alan Edwards) writes:
>X-Sun-Spots-Digest: Volume 8, Issue 180, message 14 of 15
>
>When one of our disk servers goes down, doing a 'df' on a machine that has
>the one of the disk server's partitions mounted, causes the 'df' process
>to hang PERMANENTLY.  The df process cannot be killed by kill -9.  Is
>there anything I can do to prevent this?  The machine that hangs is
>running SunOS 3.5.  Will this be fixed when we upgrade to 4.0.3?
>
>Thanks,
>-Alan

This is not likely to be fixed (and isn't fixed) in 4.0.3, since the
problem is inherent in the definition of how "hard" (the default mount)
NFS works.  There are a couple of things you can do:

1) Mount the filesystems as soft and adjust the retry and timeout values.
This is not recommended by most people, since writes can fail as opposed
to "hard" mounts where writes hang until acknoledged (as you have
noticed).  There is also a mount option called "intr".  Supposed to allow
keyboard interupts, but I don't know if that works only on mount or all
nfs operations.

2) Automount the filesystems.  You might have a better chance that they
are not mounted when the remote system goes down.

Good Luck ALAN!  From the "OTHER ALAN EDWARDS"!

 -Alan Edwards
  IX 1T-448 x34115
  (ihlpm!kae)