[Zope] Problem with database packing (major data loss)

[Richard Taylor]

We have discovered a rather nasty problem. 

On Zope 2.1.6 if you you pack the database with '0' in the days box
and then pack it again with '1' in the days box bad things happen. In
our case the first pack resulted in a Data.fs of 17MBytes (not bad
from a started point of nearly 2GBytes) the second pack (which I
assumed would do nothing) resulted in a Data.fs of 3MBytes. Great I
thought, however it also broke most of my site. Some of the symptoms
are:

Accessing existing folders gives KeyError
Many of my ZClasses are turned into DTML Methods (that is the icon
next to them in the folder view is a DTML Method icon)
All the instances of the broken classes are broken.

 
Thankfully I kept backups before performing the packs.

This is repeatable on both the servers I run.

I am now nervous of packing but have no choice. 



Richard

PS. I still think Zope is great! I am just learning slowing how to run
it defensively