I've got some scripts like the following:
/sbin/mksnap_ffs /usr /tmp/snapshot
/sbin/mdconfig -a -t vnode -f /tmp/snapshot -u 0
/sbin/mount -r /dev/md0 /usr/local/etc/snapmnt
.... (backup data, transfer data, do anything)
/sbin/mdconfig -d -u 0
/bin/rm -f /tmp/snapshot
This will sometimes more or less lock my system, since every write
access to /usr gets stuck.
ps or top show mksnap_ffs running, but apparently doing nothing, and
every attempt to kill it will fail. Not even a clean shutdown is possible.
bye & Thanks