if you occured server panic on FreeBSD 9.2 using journaled soft updates you probably had not clean shutdown and there is some inconsistency (though filesystem is clean) – for better stability disable journaled soft updates:

boot into single mode and after full fsck do:

# tunefs -j disable /dev/filesystem
# reboot

or if you want to using journaled soft updates do manual fsck in single user mode without using journal

 # USE JOURNAL? [yn] n

then the server panics should not appear to the next unclean shutdown…