Can a filing system overflow?

[moncam!loki at relay.eu.net]

We are running a WREN-IV as a second disk on a SUN 4/110, and recenty some
rather alarming things have been happening, things I have always assumed
to be impossible on a clean filing system.  We have our news on this WREN,
and it has recently been filling up (oh what a surprise!!!).  Fine, I can
accept that.  HOWEVER, I noticed that the first 1k or so bytes of the
history file (the offending file, I assume), were found in one or two
files randomly scattered around about the filing system.  Like a fool I
did not check the inode numbers, but instead took the system down and
fsck'd everything in sight - no errors.

This problem does not seem to happen unless the disk fills up.

Has anyone ever witnessed such a thing?  Is it a bug in nfs? WREN's?
Would your advise be `back everything up NOW, and get a new disk'?

Any help much appreciated.

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