[Fwd: Re: [Zope] Pack Not Working]

[Cliff Ford]

I don't know if this suggestion is relevant, workable or advisable but I 
once got out of a hole by exporting a site (i.e. folder) to a zexp file. 
That was to do with a locked Version rather than a corrupt data.fs, and 
when the site was still quite small. You could try that by importing the 
zexp into a clean data.fs (if the site appears to work despite the 
corruption).

Cliff

Tim Peters wrote:
> [Derek J. Balling]
> 
>>I'm resending this because a couple weeks later and not a single peep
>>was to be heard, and my boss is starting to hound me for insight. :-(
>>
>>Anyone have any helpful advice?
> 
> 
> If your boss is willing to pay someone to help, that opens other
> possibilities.  Otherwise this has to change:
> 
> 
>>K, now I don't mean to sound stupid, but I inherited a Zope install, and
>>I know absolutely nothing about:
>>    (a) python
>>    (b) Zope
>>    (c) the application we run on this platform (MailManager)
> 
> 
> That is, you'll have to teach yourself.  Unfortunately, you're jumping
> in at the intersection of several deep ends:  you have a corrupted
> Data.fs file, you don't have backups, and the problem first occurred a
> long time ago.  We know that with high probability because:
> 
> 
>>If I run fstest.py I get:
>>
>># python /usr/local/Zope-2.7.0/utilities/ZODBTools/fstest.py
>>/home/dballing/Data.fs
>>/home/dballing/Data.fs has inconsistent transaction length for undone
>>transaction at 475866827
> 
> 
> If you read:
> 
>     http://zope.org/Wikis/ZODB/FileStorageBackup
> 
> then you already know that .fs files grow only by appending, and your
> file is corrupt starting near byte 475,866,827.  You originally said:
> 
> 
>>  ...  Since the database is up to 5.X GB ...
> 
> 
> so the damage occurred 4 or 5 gigabytes' worth of transactions in the
> past, or some process sprayed bytes to random spots on your disk
> (e.g., flaky disk controllers can exhibit that symptom, esp. under
> high load).
> 
> When fstest.py fails, there's no (well, little) point to running fsrefs.py.
> 
> It's possible you can recover by:
> 
> 1. Bring your app down.
> 2. Make a physical copy of your Data.fs.
> 3. Learn how to use fsrecover.py, and try it on the copy.
> 
> fstest.py should pass after that.  fsrefs.py may or may not.  There's
> no guarantee it will work:  fsrecover.py proceeds simply by throwing
> away corrupted pieces of the FileStorage -- it's a very low-level
> program, with no semantic knowledge, so can create a well-formed file
> at a low level that's nevertheless missing objects crucial to your
> application.
> 
> There's simply no magical fix for file corruption, whether it's a
> FileStorage or your email folder.
> 
> It's possible (as Tres suggested) that someone reading the zodb-dev
> list would be able to volunteer more significant help than you're
> getting here.
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