[Zope] fsrecover.py won't pack

[Tim Peters]

[Andy Altepeter]
> I ran fsrecover.py on a copy of my Data.fs.  It found no errors, but then when
> it attempted to pack the file, it raised an unpickleable error, with this
> traceback:
...
>  File "/export1/Zope-2.7.5-final/lib/python/ZODB/referencesf.py", line 38, in
> referencesf
>    raise ValueError, 'Error unpickling, %s' % p
> ValueError: Error unpickling, and the rest is presumably the pickle.
>
> I receive this same error when trying to pack using the ZMI.  Any idea what's
> going on?

It suggests data corruption in your Data.fs file (assuming you're
using FileStorage).  Please read this for background info:

    http://zope.org/Wikis/ZODB/FileStorageBackup

Because fsrecover.py completed without error, best guess is that
fstest.py (described in the link above) would also complete without
error.  However, neither of those can detect "higher-level" corruption
inside serialized object state (see the link for more words).  Running
fsrefs.py (see the link again) can identify most such corruption.  So
run it and see what it says.  There is no wholly safe and automatic
way to recover from frsrefs.py-level corruption (short of reverting to
a good backup), so don't expect this to go easily.

Note that better versions of these tools exist in more recent versions
of ZODB (IIRC, you said you were running Zope-2.7.2, which corresponds
to ZODB 3.2.3 -- ZODB 3.2.9 is the current production 3.2 release).