On 6/29/20 1:31 AM, Mark Otaris wrote:
The master branch for cp now defaults to copy-on-write on
filesystems
that support reflinks, which should make copies more efficient if
Fedora starts using btrfs:
https://git.savannah.gnu.org/cgit/coreutils.git/commit/?id=25725f9d41735d....
Dolphin and KIO also seem like they will start doing this:
https://bugs.kde.org/show_bug.cgi?id=326880,
https://invent.kde.org/frameworks/kio/commit/c2faaae697f11ee600989b67b440....
Beyond these recent changes, there are many other reasons to use
btrfs, such as that Podman has a btrfs driver that might make
containers more efficient, that ostree makes limited use of reflinks
when they are available, that many filesystem options can be changed
and new features and better defaults used even after the filesystem
was initially created, that resize operations can be done online, and
that there are uniform checksums on all metadata blocks, giving
guarantees against corruption.
XFS also has reflinks, but lacks many features of btrfs, and switching
from ext4 to XFS would mean losing cgroup writeback.
That's incorrect:
commit adfb5fb46af059387eca0fce1d8cd8733f9ee3a0
Author: Christoph Hellwig <hch(a)lst.de>
Date: Fri Jun 28 19:30:22 2019 -0700
xfs: implement cgroup aware writeback
Link every newly allocated writeback bio to cgroup pointed to by the
writeback control structure, and charge every byte written back to it.
Tested-by: Stefan Priebe - Profihost AG <s.priebe(a)profihost.ag>
Signed-off-by: Christoph Hellwig <hch(a)lst.de>
Reviewed-by: Darrick J. Wong <darrick.wong(a)oracle.com>
Signed-off-by: Darrick J. Wong <darrick.wong(a)oracle.com>
-Eric