[ZODB-Dev] return of corruption errors

[Gerry Kirk]

> -----Original Message-----
> From: Tim Peters [mailto:tim at zope.com] 
> Sent: October 19, 2004 2:57 PM
> To: 'Gerry Kirk'
> Cc: zodb-dev at zope.org
> Subject: RE: [ZODB-Dev] return of corruption errors
> 
> Have you read the background info here:
> 
>     http://zope.org/Wikis/ZODB/FileStorageBackup
> 
Yes

> > The strange thing is, I don't get errors every night.
> 
> That's not strange if it *is* a HW (etc) bug.  It would be 
> strange if it were a deterministic error in the ZODB/ZEO code.

Yes, but this is on the same, unrepaired Data.fs file. One night, it has
an issue, another night, it doesn't, when running fstest.py. I do agree,
though, that there appears to be an issue here. We installed some memory
about a month back which had some conflict issues and froze up the
system a few times. Since then, I successfully ran fstest.py and
fsrefs.py, then packed the db to 1 day, to a size smaller than where the
current issue is. I've been running those tests on it nightly.

> > Is it possible that the cache files are causing some of these 
> > problems? I posted earlier that I was having BadPickleGet and 502 
> > response codes until i deleted those files.
> 
> Anything's possible here.  BadPickleGet is also a symptom of file (or
> memory) corruption, but inside object pickles.  You can 
> replace an object pickle with any string of nonsense bytes 
> whatsoever, and that can't hurt anything fstest looks at 
> (fstest knows nothing about application objects -- fstest 
> doesn't even import the pickle module).  So you're seeing 
> corruption both inside pickles, and in the FileStorage "glue" 
> that holds pickles together.  To me, that strongly suggests a 
> deeper HW/firmware/network/system bug of some kind.  If 
> possible, try running your app on a different box?
> 
I no longer had the BadPickleGet error after remove the cache files. I
will look into trying the system on another machine... Will take some
time.

- Gerry