[Discuss] btrfs

[gaf at blu.org (Jerry Feldman)]

Essentially, btrfs has been mentioned in a number of other contexts, but
since it is now available on several distros, let's just start a thread
on btrfs.
Here is a link to the main Wiki:
https://btrfs.wiki.kernel.org/index.php/Main_Page

First we have an installfest coming up next week on March 2nd I may want
to explore using btrfs in some cases. First, in the case of an in-place
upgrade what advantage do you really have using btrfs in a non-raid
situation.
Essentially there will be no redundancy of the metadata.

Most of the examples I have seen are to install btrfs on raw drives. For
instance 'mkfs.btrfs /dev/sdb /dev/sdc', this will set up the data as a
RAID0 (non-redundant) and the metadata as a RADI1 (redundant). The
advantage here is that a typical RAID1 is fully redundant but you are
using 2 drives (actualy partitions) for 1 drive worth of data. With the
default btrfs formatting your metadata is redundant,, but your data is
essentially stripped (RAID0) so you effectively get more storage with
the safety of RAID1. (You can configure btrfs to be fully redundant if
you want to).

So, our typical install at an installfest is to a single drive, possibly
with a pre-existing Windows on a laptop. What might be the advantage of
using btrfs today over ext4 for a new user. Fedora 18 certainly gives
you the option of using ext4 or btrfs.

A more detailed question is using btrfs on an install in a single or
multi-disk clean install from scratch, can you set up a btrfs as boot
drive. AFAIK, yes, but I have seen issues online. One issue is that
btrfs automatically compresses files, but GRUB needs stuff not to be
compressed.

-- 
Jerry Feldman <gaf at blu.org>
Boston Linux and Unix
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