[Zope-dev] Weird Data.fs corruption...

[Carl Robitaille]

Hi everybody,

	I looked around the Zope site and mailing lists, but I wasn't able to
find an answer to my problem. I'm using the CVS version of Zope2. I did
an update yesterday. Since then, there's been some commits.

	I just started my web site project using Zope running with ZServer,
when I began to have problems doing Cut-Paste operations. I thought at
first that I messed the permissions or something because of my lack of
experience with Zope. Little did I know at that moment that my Data.fs
was corrupted very badly. So I tried to restart Zope, but it refused
giving me this backtrace:

[zope@petechie ~/Zope2]$ ./start
Traceback (innermost last):
  File "/home/zope/Zope2/z2.py", line 554, in ?
    exec "import "+MODULE in {}
  File "<string>", line 1, in ?
  File "/home/zope/Zope2/lib/python/Zope/__init__.py", line 110, in ?
    DB=ZODB.FileStorage.FileStorage(Globals.BobobaseName)
  File "/home/zope/Zope2/lib/python/ZODB/FileStorage.py", line 303, in
__init__
    self._pos, self._oid, tid = read_index(
  File "/home/zope/Zope2/lib/python/ZODB/FileStorage.py", line 1515, in
read_index
    if read(4) != packed_version: raise FileStorageFormatError, name
ZODB.FileStorage.FileStorageFormatError:
/home/zope/Zope2/var/Data.fs           

	I then logged to Zope web site to get information on how to get my
Data.fs fixed. I read the
http://www.zope.org/Members/itamar/CorruptedZODB document and downloaded
the tranalyzer.py python program. I then understood what the backtrace
already told me. The first 4 bytes of any ZODB files should be something
like "FS21". Instead, I have garbage in my Data.fs:

[zope@petechie var]$ python tranalyzer.py Data.fs | more
Traceback (innermost last):
error: Not a .fs file (at least, not a kind I know about)
magic = 
6TĘ                                                                    

	Just for the record, Data.fs.in is read easily by tranalyzer.py.

	How can this happen? Any idea? My only "guess" is that it has to do
with the Data.fs file being used by ZServer over an NFS partition on
Linux. This is only a guess, but I really can't see any other thing I
could have done wrong.

	This doesn't really bug me for the moment as I only had a couple of
hours put in my site, but I would like to prevent it from happening
again.... yes I do backups, but only once a day ;-)

	Thanks for your help/comments.

Carl

Carl Robitaille
robitail@giref.ulaval.ca