Dump an Unmounted Journaled UFS Filesystem

[Warren Block]

On Tue, 1 Jul 2014, Dan Plassche wrote:

> I understand that using dump is not currently recommended on a mounted
> journaled UFS2 filesystem.  I prefer to boot from a separate FreeBSD drive
> for cold backups anyway, so I'm wondering if there are any issues with
> running dump on an unmounted journaled filesystem?  All the discussions
> I've seen seem to focus on disabling journaling completely, which I would
> like to avoid.

The snapshot code in sys/ufs/ffs/ffs_snapshot.c still prevents making 
snapshots on SUJ filesystems.

So pick the way that seems best: dump without a snapshot, use something 
other than dump like rsync, or turn off SUJ:
https://forums.freebsd.org/viewtopic.php?&t=41503

Some people have mentioned that they see crashes more frequently with 
SUJ enabled, so it might be both the cure and part of the problem.