NFS lockup when copying a "special" file

Oliver Fromme olli at
Tue Sep 5 11:38:57 UTC 2006

Oliver Lehmann wrote:
 > Oliver Fromme wrote:
 > > This doesn't seem to be amd64-specific, so I copy freebsd-fs.

I still think it's not amd64-specific.

 > > [...]
 > > > > nfs server www:/mnt/space/www: not responding
 > > > > nfs server www:/mnt/space/www: not responding
 > > > > nfs server www:/mnt/space/www: not responding
 > and again it hit me two times today where I was forced to reboot my
 > client... this all makes me feel kinda sad - Is there anything which can
 > be done to help fixing this?

Did you try any of the suggestions in my previous mail?
E.g.:  use TCP NFS transport instead of UDP, and/or force
NFSv2 instead of NFSv3.  You could also try lowering the
MTU (although I think it's not the cause of the problem
in your case, but it might be worth a try nonetheless).

What are your NFS mount options?  What is the size of the
file on which the mount became stuck?  Do the contents of
the file matter?  i.e. when you create a file of the same
size with dd(1) that contains only zeroes, can you copy
it to the NFS share?

A bit of tcpdump output might be helpful, too.  Please use
the options "-vv -s1600", otherwise it's useless.

 > I nearly lost a really really important pdf
 > which was generated online and my browser became stuck on showing me the
 > "save as" dialog...

If it happens again, you can mount the NFS share again
over the same mount point.  Of course that's only an
emergency measure, not a solution (and it won't help if
an application is accessing the offending file again).

Best regards

Oliver Fromme,  secnetix GmbH & Co. KG, Marktplatz 29, 85567 Grafing
Dienstleistungen mit Schwerpunkt FreeBSD:
Any opinions expressed in this message may be personal to the author
and may not necessarily reflect the opinions of secnetix in any way.

"One of the main causes of the fall of the Roman Empire was that,
lacking zero, they had no way to indicate successful termination
of their C programs."
        -- Robert Firth

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