

Fedora 16 To Use "Btrfs" Filesystem By Default - dkd903
http://digitizor.com/2011/06/09/fedora-16-btrfs/

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rwmj
This is not definite. The feature has to go through a bunch of hoops
first[1][2]. It was only conditionally approved in the meeting yesterday,
assuming everything works by the time F16 comes around. Previous big features
have been pulled at the last minute (notably systemd in F14 was pulled right
before release[3], and only made it into F15).

[1]
[http://fedoraproject.org/wiki/Talk:Features/F16BtrfsDefaultF...](http://fedoraproject.org/wiki/Talk:Features/F16BtrfsDefaultFs)

[2]
[https://bugzilla.redhat.com/showdependencytree.cgi?id=689509...](https://bugzilla.redhat.com/showdependencytree.cgi?id=689509&hide_resolved=1)

[3]
[http://article.gmane.org/gmane.linux.redhat.fedora.devel/139...](http://article.gmane.org/gmane.linux.redhat.fedora.devel/139851)

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rlpb
brtfs doesn't have an fsck yet. I've been waiting for it before I try it. Is
it really safe to go ahead without this, or will it be ready by release?

[https://btrfs.wiki.kernel.org/index.php/FAQ#When_will_Btrfs_...](https://btrfs.wiki.kernel.org/index.php/FAQ#When_will_Btrfs_have_a_fsck_like_tool)

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cycojesus
as someone with a btrfs partition containing a handful of broken inodes
(according to btrfsck), I'd say wait. btrfsck takes ages during each boot AND
cannot fix problems. I'll switch back to ext4 when I find the time (and a plug
compatible for my external drive.)

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nodata
Last time I checked, btrfs had a read-only fsck implementation, i.e. it could
find errors but not fix them. I hope fsck is finished and stable now (the
project page still says fsck is not available).

Edit: this also means Fedora doesn't use LVM by default anymore

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danssig
>this also means Fedora doesn't use LVM by default anymore

Uh, that's pretty big. How will I resize partitions on the fly?

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danvet
It's the "by default" that's important. You can still use lvm to resize your
partitions. But resizing volumes within the btrfs partition will be done by
the btrfs tools.

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pixelbeat
Cool we can have reflinks by default.

<http://www.pixelbeat.org/docs/unix_links.html>

Fedora changes seem to go in cycles. F11 and F14 were good stabilization
releases. F17 should be of the same ilk I think.

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daedhel
The comments, so far, seem to perceive this change as negative. I, myself,
think it is something really good for the overall innovation int the FOSS
ecology to have a distro comited to testing new features.

~~~
evangineer
Good point. The flipside of that is that such a distro is less suitable for
production servers.

That said, a savvy sysadmin would be picky about the filesystem to use in
production anyway and could easily use a non-default filesystem.

~~~
daedhel
Well the thing is that Fedora is the testing platform for RedHat.

Fedora is for the desktop users, it is used to test new features, and what RH
finds interesting, they add it to their server oriented distro, Red Hat Linux.

So, the fact that Fedora is not server oriented is by design.

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naner
Well I guess this is one way to speed up development and testing. I don't
think the disk format is even finalized yet.

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sigzero
"It will probably not be known until August or September whether Fedora 16,
which is planned for the end of October, will actually use Btrfs as the
standard, because testers and developers need time to gain additional
experience with the upcoming alpha and beta versions."

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Legion
I can't wait. Btrfs has been lingering in "almost ready" state for a while and
it seems like the only thing that will kick things to the next level is the
threat of it actually being used.

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br1
Filesystems lose on a big opportunity by supporting hardlinks. If every file
had only one name, files on the same directory could be stored closely, much
improving locality.

~~~
derobert
That'd only really be true if a significant portion files were hardlinked. My
root filesystem (Debian GNU/Linux testing) has 393,410 files, of which 825
have more than one link. My /home has 0 out of 156,273 files hardlinked.

Having 0.2% (or less) of files hardlinked shouldn't prevent storing files in
the same directory near each other.

~~~
rcfox
The point is that just the possibility of having more than one link kills your
ability to assume that there is only one. It has nothing to do with whether or
not they actually have more than one link.

~~~
koenigdavidmj
Right, but this bumps into a spatial-locality analogue of Amdahl's law. If you
optimise case that shows up 1% of the time, then you can only get a total gain
of 1%.

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archangel_one
No, the point is that you can't optimise the other 99% because that
optimisation only works if hardlinks aren't allowed.

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viraptor
Why not? Choose parent at random and place the file near children of that
parent. In 99% of cases it's the only parent, so you get the result you aimed
for. Why would it be prevented by possible other names?

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PaulHoule
ouch... i'm conservative when it comes to filesystems; i had to revert from
ext4 to ext3 on Amazon's EC2 because ext4 had more trouble with EBS... every
other time I've tried a new filesystem i've had trouble with wrecks and data
corruption... making a whizzy new filesystem the default will cause a lot of
pain

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tytso
Hey, I'd really appreciate it if you could send a report of your experiences
to linux-ext4@vger.kernel.org. This is the first I've heard of issues with
ext4 with EBS, and I'd love to know more. (Also, please mention the kernel
version you are using; one possibility is that EC2 kernels tend to lag
upstream kernels, and ext4 has had a lot of bug fixes since a RHEL or SLES
kernel of 2.6.32/2.6.34 --- upstream is at 2.6.39, and we're about to release
version 3.0. :-)

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cultureulterior
Does it support raid5/6 yet?

~~~
drdaeman
This is not a filesystem's job.

