btrfs advice? - users - Fedora mailing-lists

30 May 2011


      I made the leap to a btrfs root partition for my netbook with a fresh
install of F15.
Everything seems to work fine and I have done some fair amount of
Googling for information and come across
https://btrfs.wiki.kernel.org/index.php/Getting_started which offers
some great (incomplete) info but nothing Fedora specific. I have some
questions about how to move forward to take advantage of btrfs:
1) Is there any kind of integration of btrfs with the included apps
(For example: automatic snapshots before yum updates allowing easy
rollbacks, deja dup backing up a btrfs snapshot so that currently
changing data doesn't affect the backup process, a kiosk mode that
rolls back a home directory to a known state after logout, etc.) or is
that the next step to take advantage of all the new bells and whistles
and F15 is just a test-btrfs-as-a-ext4-replacement release?
2) I see (using 'mount') that the root is btrfs along with some (what
appear to be) subvolumes for /tmp, /var/tmp and /home yet 'btrfs
device scan' shows no information. Does 'btrfs device scan' only scan
unmounted devices or is this a bug?
3) I have read at Phoronix that using the transparent compression
offers a fair performance gain (
http://www.phoronix.com/scan.php?page=article&item=btrfs_space_cache&...
) with mixed results when combining that with space cache. Has the
space cache+compression degradation seen in some benchmarks been fixed
in F15? Also, is using transparent compression simply a matter of
adding the correct mount flag to /etc/fstab or is there a more complex
conversion process to be followed that needs to be done offline?
4) Since this is a netbook with a modest Atom processor, would
enabling transparent compression just load the CPU such that any
performance is negated or cause significant battery drain?
Thank you for any experience you have to offer.
/Mike