mksnap_ffs woes

[Kris Kennaway]

On Wed, Mar 30, 2005 at 02:42:41PM +0100, Andrea Venturoli wrote:
> Hello.
> 
> 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/umount /usr/local/etc/snapmnt
> /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.

mksnap_ffs may sometimes take a long time (order of tens of minutes)
to generate the snapshot.  During this time, other writes to the
filesystem may be suspended.  Are you sure this isn't what you're
seeing?

Kris
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