[Zope] The Goblins of Zope

Dieter Maurer dieter@handshake.de
Tue, 14 Jan 2003 19:32:44 +0100


Toby Dickenson wrote at 2003-1-14 10:18 +0000:
 > ...
 > If a unix filesystem did not have a competent "fsck" tool, would you use 
 > it in 
 > production? 
If the physical structure of the Unix file system were as trivial
than that of FileStorage, then maybe...

 > ...
 > How does anyone know for sure that there is no problem in their storages 
 > today 
 > without using a "fsck" tool?
You are much deeper in "Storages" than I am.

I have the feeling that a "FileStorage" is a linear sequence
of transaction records. When Zope builds the "FileStorage" index,
I expect (I never verified) that is analyses the linear sequence
and checks that at least the record sizes are correct (otherwise,
with high probability, invalid transaction records would be encountered).
Besides this elementary structure, there are backpointers from
newer to older versions.

Thus, I expect, that damage to the record structure (modifying the
length of a record) would be detected the next time when Zope
starts.
Damage inside a transaction record may not be detected.

But, if the problem indeed, is unnoticed for a long time, then
it does not seem to be that grave.


Dieter