Does this look like a sane method for moving an existing internal log to
an external device?
/dev/nvme0n1p1 2GB Journal mirror 0
/dev/nvme1n1p1 2GB Journal mirror 1
/dev/sda1 16TB XFS
# mdadm --create /dev/md0 --level=1 --raid-devices=2 /dev/nvme0n1p1
# mkfs.xfs /dev/sda1
# xfs_logprint -C journal.bin /dev/sda1
# cat journal.bin > /dev/md0
# xfs_db -x /dev/sda1
xfs_db> write -d logstart 0
# mount -o logdev=/dev/md0 /dev/sda1 /mnt
It seems to "work" and I tested with a whole bunch of data. I was also
able to move the log back to internal without issue (set logstart back
to what it was originally). I don't know enough about how the filesystem
layout works to know if this will eventually break.
*IF* this works, why can't xfs_growfs do it?