After heaving trouble during heavy IO with 9.0, 9.1 and 9.2 FreeBSD machines, I removed journaling
and switched back to softupdates on / filesystem.

Here is how to remove journaling of /

1) Boot to single user mode


tunefs -j disable /
mount -o rw /
chflags noschg,nosunlnk /.sujournal
rm /.sujournal
mount -o ro /
fsck /
mount -o rw /
reboot