[Zope] Fun with FSRECOVER

[Paul Winkler]

On Thu, Feb 06, 2003 at 05:24:33PM -0700, Edward Pollard wrote:
> I caught wind of fscheck and fsrecover via a discussion on this list. A
> test run on a backup of the data.fs file gave some interesting results.
> 
> The interesting parts of the output are included below.
> 
> So, can someone tell me what this all means, and what I should do with
> it? Would swapping in the "recovered" data.fs result in data loss?

It might. 1.9 MB of data was thrown away. If all of this is
old undo data, you're OK. Otherwise you've lost something.
Unfortunately there's no easy way to find out *what* data was
removed - a major problem with fsrecover IMHO.

It may be worth playing with the command-line options, too.
I tried the -P option ("partial") on a heavily damaged 
database and it recovered a lot more data. OTOH, this option requires
-p 0 ("pack all undo data") so you lose all your undo...
In our case it was well worth it since we hadn't been running
fscheck regularly and I was chagrined to discover that I had
NO undamaged backups.

> I'm
> not really sure what fsrecover does, although I've seen it implied that
> its a good thing.

It's a bit of a black box to me too... 

-- 

Paul Winkler
http://www.slinkp.com
Look! Up in the sky! It's THE CRANBERRY!
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