Bug#646699: Fwd: Re: Bug#646699: btrfs: Installer offers BTRFS an optional filesystem
On Thu, 27 Oct 2011 10:24:05 +0200, Gaudenz Steinlin <gaudenz@debian.org>
wrote:
> On Wed, 26 Oct 2011 23:21:33 +0530, Christian PERRIER
<bubulle@debian.org>
> wrote:
>> severity 646699 important
>> reassign 646699 partman-btrfs
>> retitle 646699 Please make partman-btrfs optional as BTRFS is too
>> unstable
>> thanks
>>
>> Quoting Gergely Nagy (algernon@balabit.hu):
>> > reassign 646699 debian-installer
>> > thanks
>> >
>> > Maarten <mvrossen@gmail.com> writes:
>> >
>> > > Package: btrfs
>> > > Severity: critical
>> > > Justification: causes serious data loss
>> > >
>> > > BTRFS shouldn't be offert as a option filesystem in the debian
>> > > installer.
>> > > It is unsafe to use. Quallity is poor. No recovery possible on
>> > > filesystem errors. (The btrfs driver will even crash on a
filesystem
>> > > error)
>> > > The provided tool btrfsck doesn't actually do anything.
>> > > There doesn't seem to be any progres on a working btrfsck.
>> > >
>> > > Atleased users should be warned to not use it, unless they don't
>> > > care about dataloss
>
> Do you have any real world cases to support these claims using a recent
> kernel version (at least the version currently in testing).
My btrfs filesystem crashed running the latest squeeze kernel. I don't
know why. Maybe I ran out of power or something like that
When the initrd mounts the filesystem it gets a segfault.
I booted a Ubuntu 11.10 live CD. It also did a segfault when I mounted the
filesystem.
After i realized btrfsck doesn't do anything, I moved the filesystem with
dd to an image file external usb-hd and i reinstalled my laptop.
I'm not the only one with this problem just google on "btrfs mount
segfault"
I was lucky that I had my important data on an other filesystem. I'm just
worried about all the users using this filesystem because it is offered as
stable by Debian, while it isn't ready yet.
Filesystem corruptions happen on any filesystem. On btrfs there is just no
way to recover from one. Chris Mason apparently is having difficulties
writing one our he has other priorities.
http://www.mail-archive.com/linux-btrfs@vger.kernel.org/msg08383.html
http://www.mail-archive.com/linux-btrfs@vger.kernel.org/msg11837.html
The point is as long as there is no btrfsck which works included in Debian
it shouldn't be offered by the default installer. And certainly not
without
a warning.
>
>> >
>> > There is no btrfs package in Debian, thus, this report did not reach
>> > any
>> > developers. Furthermore, since it is the installer that is allegedly
at
>> > fault, it should be filed against the debian-installer package.
>> >
>> > I went ahead and reassigned it there.
>>
>>
>> Well, if btrfs is in such a bad shape, then partman-btrfs should be
>> made optional so that only those people who really want it will have
>> it as an option.
>>
>> I don't think that dropping the package entirely is the best
>> option. But making it less "visible" in D-I is probably good if I
>> believe in the above claims (I have no idea about this to be true or
>> not).
>
> With my own experience with BTRFS I can not support the above claims. In
> several tests and while running my laptop with BTRFS I never saw any
> data loss. While it's true that there is no external filesystem checker
> (aka "btrfsck") as this is a journaling filesystem such a tool is much
> less needed than for a non journaling filesystem. Also a btrfsck tool
> is in the works, but it's unclear when it will be released.
>
> The main reason why I would not recommend btrfs on Debian for / is it's
> very
> poor fsync performance which makes apt runs a pain in the ass if you
> don't use "eatmydata" which disables fsync. But that's a performance and
> not a corectness issue.
>
> BTRFS might be unreliable with the current stable kernel. I did not test
> this. So if someone really belives that BTRFS should be less visible,
> just do that for the stable installer (if thats possible wrt stable
> update policies).
>
> Gaudenz
Filesystem corruption does also happen in other journaling filesystems.
I'm running a lot of servers at work and I do need fsck at times, to get a
filesystem to mount again.
Believe me when I say that using a filesystem without having a way to
recover from filesystem corruptions is stupid. Journaling can't always
save
you. (bugs, drive defect, firmware etc)
Regards,
Maarten
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