Re: interest in post-mortem examination of a BTRFS system and improving the btrfs-code?

[Jeff Mahoney <jeffm@suse.com>]

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On 3/31/19 2:44 PM, btrfs@avgustinov.eu wrote:
> Dear all,
> 
> 
> I am a big fan of btrfs, and I am using it since 2013 - in the meantime
> on at least four different computers. During this time, I suffered at
> least four bad btrfs-failures leading to unmountable, unreadable and
> unrecoverable file system. Since in three of the cases I did not manage
> to recover even a single file, I am beginning to lose my confidence in
> btrfs: for 35-years working with different computers no other file
> system was so bad at recovering files!
> 
> Considering the importance of btrfs and keeping in mind the number of
> similar failures, described in countless forums on the net, I have got
> an idea: to donate my last two damaged filesystems for investigation
> purposes and thus hopefully contribute to the improvement of btrfs. One
> condition: any recovered personal data (mostly pictures and audio files)
> should remain undisclosed and be deleted.
> 
> Should anybody be interested in this - feel free to contact me
> personally (I am not reading the list regularly!), otherwise I am going
> to reformat and reuse both systems in two weeks from today.
> 
> Some more info:
> 
>   - The smaller system is 83.6GB, I could either send you an image of
> this system on an unneeded hard drive or put it into a dedicated
> computer and give you root rights and ssh-access to it (the network lin
> is 100Mb down, 50Mb up, so it should be acceptable).
> 
>   - The used space on the other file system is about 3 TB (4 TB
> capacity) and it is distributed among 5 drives, so I can only offer
> remote access to this, but I will need time to organize it.
> 
> If you need additional information - please ask, but keep in mind that I
> have almost no "free time" and the answer could need a day or two.

My team is always interested in images of broken file systems.  This is
how --repair evolves.  Images with failed --repair operations are still
valuable.  That's the first step most users take and why wouldn't they?
 If --repair is misbehaving, the end result shouldn't be "I hope you
have backups."

It's not the size of the file system that matters so much.  The data on
it doesn't matter from a debugging perspective and, in any event, it's
not written to the image file anyway.  I do want a btrfs-image file from
the file system, and if btrfs-image fails to create a usable image,
that's also valuable to know and fix.

Thanks,

-Jeff

-- 
Jeff Mahoney
SUSE Labs


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