With that said, see the stability section on the wiki
You can boot a btrfs root (/boot) partition with grub2 (1.99), but the initrd has to be compressed with zlib (not lzo)
Looking as /etc/initramfs-tools/initramfs.conf, gzip appears to be the default, you should be good to go.
And from the ubuntu wiki page I gave you :
As of 11.04-beta1, it is possible to use only btrfs file systems with the caveat that grub _MUST_NOT_ be installed to the boot sector of the btrfs volume containing /boot.
So install Ubuntu 11.04 or higher, be sure to install grub to the MBR (this is the default behavior of the installer).
You have been able to install Ubuntu into btrfs since 10.10
See the following guides
https://help.ubuntu.com/community/btrfs
http://ubuntuforums.org/showthread.php?t=1389279
With that said, see the stability section on the wiki
You can boot a btrfs root (/boot) partition with grub2 (1.99), but the initrd has to be compressed with zlib (not lzo)
Looking as /etc/initramfs-tools/initramfs.conf, gzip appears to be the default, you should be good to go.
And from the ubuntu wiki page I gave you :
So install Ubuntu 11.04 or higher, be sure to install grub to the MBR (this is the default behavior of the installer).