FileSystem > Btrfs
Btrfs is intended to address the lack of pooling, snapshots, checksums, and integral multi-device spanning in Linux file systems, these features being crucial as the use of Linux scales upward into larger storage configurations. Btrfs is designed to be a multipurpose filesystem, scaling well on very large block devices.
Even though Btrfs has been in the kernel since 2.6.29, the developers state that "as of 2.6.31, we only plan to make forward compatible disk format changes". The developers still want to improve the user/management tools to make them easier to use. For more information about Btrfs, follow the links in See also section.
Ext2/3/4 filesystems should be upgradable to Btrfs (but not the other way around).
DebianSqueeze and later support Btrfs. This means that they include a compatible kernel and tools. However, using the most recent kernel and tools from backports (rather than those in the stable releases) is often recommended.
A Btrfs volume created on a raw partition can be used to boot, however, it may require a hack for initramfs, this is particularly relevant for multi-disk (e.g. RAID1) where UUID syntax must be used in fstab #612402
The DebianInstaller can format and install to single-disk Btrfs volumes. The way that Btrfs combines multiple disks to create a single volume is not compatible with the data model of the current installer (#686097). Various people have described ways of installing Debian onto a RAID1 Btrfs without too much trouble.
/usr/share/doc/linux-doc-2.6.*/Documentation/filesystems/btrfs.txt.gz, also available online for 2.6.32
Btrfs wiki: https://btrfs.wiki.kernel.org/
Btrfs on Wikipedia
Debian 6.0 "Squeeze"
dpkg-divert --add --rename --divert /sbin/fsck.btrfs.real /sbin/fsck.btrfs
And create the executable file /sbin/fsck.btrfs with this wrapper by exemple:
/sbin/btrfsck $(echo $@ | sed -e "s/\($1\)\|\(-a\)//g")
Btrfs mailing list: firstname.lastname@example.org