Mailinglist Archive: opensuse-factory (776 mails)

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Re: [opensuse-factory] Re: [opensuse-kernel] BtrFS as default fs?
On 9/11/13 6:16 AM, Dirk Müller wrote:
Hi Matthias,

Besides Scalability there are other attributes where
btrfs exceeds other filesystems.

Regarding the scalability part, lets not compare something from 3
years ago, lets compare the 13.1 kernel, kernel 3.11.0. Ext4 has had
pretty nice improvements in 3.11 regarding scalability, see
http://lkml.indiana.edu/hypermail/linux/kernel/1307.0/00286.html for
details.

http://www.phoronix.com/scan.php?page=article&item=linux_311_filesystems

You might or not like this benchmark, but the headline is pretty
clear: "EXT4 wins".

Also, did btrfs fix the backlink issue? that seems to be a major
scalability burden actually.

Again, yes:

commit f186373fef005cee948a4a39e6a14c2e5f517298
Author: Mark Fasheh <mfasheh@xxxxxxx>
Date: Wed Aug 8 11:32:27 2012 -0700

btrfs: extended inode refs

This patch adds basic support for extended inode refs. This includes
support
for link and unlink of the refs, which basically gets us support for
rename
as well.

Inode creation does not need changing - extended refs are only added
after
the ref array is full.

Signed-off-by: Mark Fasheh <mfasheh@xxxxxxx>

The current issue is the ability to enable them online. I have patches
to do that posted to the btrfs mailing list.

-Jeff


And just to compare the _scalability_ we're talking about. the corner cases
are:

BTRFS supports filesytems up to 16384 Petabytes. Ext4 has a slight
disadvantage here, only spporting filesystems up to 1024 Petabytes.
While that sounds like a serios scalability issue for SLE, it is less
of a concern for the typical openSUSE case.

Other scalability marks are not that interesting. But if we care about
scalability and SSD support, F2FS might be interesting to look at as
well..


Greetings,
Dirk



--
Jeff Mahoney
SUSE Labs

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