This has happened only twice. The backup runs at 6:30 and takes about ten minutes. Both times, /var/log/system.log looks like this just before the log entries showing where I started the system again:
Code:
Oct 2 06:41:02 slynew diskarbitrationd[42]: applet [1513]:34843 not responding.
Oct 2 06:41:03 slynew kernel[0]: jnl: close: flushing the buffer cache (start 0x66a200 end 0x66c400)
I'm backing up to one of three partitions on a FireWire drive. I leave the mirror backup partition unmounted (with the other two mounted) after discovering that SuperDuper can mount and unmount that partition on its own.
I haven't actually witnessed the shutdown, and it doesn't happen every time the backup runs. I'm judging based on the logs and some circumstantial evidence (someone telling me he couldn't ping my system sometime just before 7:30) that the shutdown is happening right after the backup runs.
So I don't know that its connected to SuperDuper, but before calling Apple I thought I'd ask if anyone else has experienced this and/or if any of the above is illuminating.