Using sysctl:
$ sysctl vfs.numvnodes vfs.zfs
$ sysctl kern | grep kmem

gstat

All the arc stats can be retrieve via sysctl… e.g. sysctl kstat.zfs.misc.arcstats

2gb set 9:39 24/10 Uptime; ater rebuild, 4Gb set on 28/10 9am

have an issue where ZFS consumes all available memory as a result of that same periodic 100.chksetuid script running. It normally grinds the machine to a halt but I think I've also had a panic.

Could you set up a log of the zfs sysctls like: Code:

export ZFSLOG=/tmp/vfs_zfs.log; while true; do date » $ZFSLOG; sysctl vfs.zfs » $ZFSLOG; sleep 30; done

and see what the vfs.zfs.arc_meta_used is before it crashes?

http://forums.freebsd.org/showthread.php?t=30021

http://www.freebsd.org/doc/en/books/developers-handbook/kerneldebug.html