From: Jay R. Wren (jrwren@oakland.edu)
Date: Mon Nov 18 2002 - 16:57:11 EST
Hello Managers,
We are having a very interesting issue with an NFS server of ours.
The Symptom:
A user edits a file(from fs mounted via nfs) using the pico
editor(from the pine package washington.edu). The user saves changes.
The user opens the file again and it looks empty.
In fact it is not empty. The file is full of nulls. The length of
nulls is the size of the file after the user edited it. For Example, I
open myfile.txt and save the 6000 byte file. When I read the file it
looks empty, but is actually still 6000 bytes. I say it looks empty
because most editors, vi, pico don't show nulls. Even cat and more
don't show nulls. So far less, and maybe emacs, show nulls.
This doesn't happen every time, which is what makes it so horrible.
We are 99% sure it only happens with pico, but we are starting to see
some other issues that cast doubt on that.
Even more strange is the fact that these files full of null do not
appear full of null if we look at them locally on the nfs file server.
The file contents are all there, but if we look at them on any nfs
client, the file is full of nulls.
The Environment:
NFS Server is Tru64 5.1A exporting /home (an advfs filesystem) via
NFS. Clients include 4.0d, 4.0f, as well as Linux and Solaris. Linux
is the only NFS client which we could not replicate the bug on.
Solaris and all Tru64 versions seem to write null files.
I could probably fill a couple more pages of things we have tried, tcp
vs. udp mount points, mounting from different sides of the NAT(1 to 1)
box. Nearly all of the clients are on the different side of the NAT
device, but it doesn't matter, moving the client to the side of the NAT
which hosts the NFS Server does not fix the problem. We have tried
with and without automount. We have tried a different NFS Server Tru64
5.1a, and been unable to replicate the problem but changing to a
different server is not practical nor should it be necessary.
Someone reported a very similar problem to the list a few months ago,
but their problem was directly with ADVFS and PICO and was not an NFS
issue, our problem seems slightly different, especially considering the
fact that the original file without nulls can be viewed on the NFS
Server.
Any insight is appreciated.
Thanks
-- Jay R. Wren Systems Programmer Oakland University Rochester, Michigan
This archive was generated by hypermail 2.1.7 : Sat Apr 12 2008 - 10:48:59 EDT