[Openstack-operators] XFS documentation seems to conflict with recommendations in Swift

[Jonathan Simms]

Hello all,

I'm in the middle of a 120T Swift deployment, and I've had some
concerns about the backing filesystem. I formatted everything with
ext4 with 1024b inodes (for storing xattrs), but the process took so
long that I'm now looking at XFS again. In particular, this concerns
me http://xfs.org/index.php/XFS_FAQ#Write_barrier_support.

In the swift documentation, it's recommended to mount the filesystems
w/ 'nobarrier', but it would seem to me that this would leave the data
open to corruption in the case of a crash. AFAIK, swift doesn't do
checksumming (and checksum checking) of stored data (after it is
written), which would mean that any data corruption would silently get
passed back to the users.

Now, I haven't had operational experience running XFS in production,
I've mainly used ZFS, JFS, and ext{3,4}. Are there any recommendations
for using XFS safely in production?