[ZODB-Dev] ZODB Problem

[Bob Horvath]

Tim Peters wrote:

>[Alexey V Paramonov]
>  
>
>>I have already solved the problem:
>>    
>>
>
>Congratulations!
>
>  
>
>>I have several backups of Data.fs, one of them (very old) was "alive".
>>So, I starget to cut pieces from the end of Data.fs and tried to load
>>it, so after a few hours I knew which trasaction was malfromed.
>>    
>>
>  
>
...

>Now you know why there's no automated way to recover from arbitrary damage.
>Don't know whether "0032" and "0033" are decimal or hex, but it looks like
>they're early transactions in the life of this database.  Given that
>FileStorage grows only by appending:
>
>    http://zope.org/Wikis/ZODB/FileStorageBackup
>
>do you have any idea how bytes early in the file may have gotten damaged?
>There are rare reports of that, but outside of flaky hardware or system
>software no cause is evident.  It's scary when once-good data goes bad for
>no identifiable reason.
>
>  
>

I have seen this comment made several times on this list, and while it 
may in fact be true, it seems suspect to me.  Considering how many 
people come out of the woodwork complaining about corrupted Data.fs 
files, if it were flaky hardware or system software, you would think 
lots of non-ZODB files and applications would have similar problems.  My 
gut suspicion is that these are caused by some yet to be identified 
software bug.

Has anyone ever tried to compile data on what sorts of machines or 
operating systems corrupt files seem to occur on?   If it is flaky 
hardware, you would think you would have more than one person at the 
same hosting outfit with similar problems.  If it is system software, 
then you woudl see some correlation on Windows, vs. Linux, vs. FreeBSD, 
etc.