Re: Can't mount, power failure - recoverable?

[Hugo Mills <hugo@carfax.org.uk>]

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On Sat, Mar 17, 2012 at 04:24:02AM +0000, Skylar Burtenshaw wrote:
> Hey all. First and foremost, great work on the filesystem. Love it. That is,
> until this...
> 
> AGES ago, I had a power failure. I had 22 drives in one BTRFS filesystem. I
> know, dumb idea given that it's an experimental FS, but it's not important data,
> just.....LOTS of it. A dozen terabytes or so.

> Now when I try to mount it with all present kernels (up to 3.2.0) I
> get several minutes of disk churning, and a kernel stack trace.
> Every tool I throw at it fails. find-root only shows one tree (at
> the very end) after complaining about blocks seeming great, but
> generations don't match for ages.

   Can you give us the last, say, 200 lines of find-root's output?
Does it give you any listings for "root objectid"s? With find-root and
recover, it's not necessarily fatal that the transids/generations
don't match.

> The btrfsck from the stable tree lists twenty "item # key" messages,
> then stops with "failed to find block number 20975616" and aborts
> every time.

> I've been sitting on this filesystem for half a year now, using my
> backup array, but it's getting full. I realize I'm being very sparse
> on information, but I'm not sure what you need from me.

   Only half a year? :) I sat on my broken 6TB array for a year before
I gave up and recovered the data I didn't have in backups... (And for
the same reason you have -- I ran out of space on the secondary
storage)

   Hugo.

-- 
=== Hugo Mills: hugo@... carfax.org.uk | darksatanic.net | lug.org.uk ===
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