rc.d script for memory based zfs intent log

[John]

Hi Folks,

   Here's an rc.d script that provides a nice performance boost on
ZFS/NFS based file servers. It also helps in other areas not specific
to NFS.

   It attaches the log device at system startup and removes it at
system shutdown time. Example;

memzil_pools="tank"
memzil_bootfs="YES"
service memzil onestart
zpool status tank
service memzil onestop

   This configuration provides a nice performance boost especially to
NFS, but also helps in other areas not specific to NFS.  

   Please DO NOT USE this script if your system is not UPS backed, preferably
with dual power supplies on separate circuits. If your system crashes you
may lose data. The script contains information on recovery.

http://people.freebsd.org/~jwd/memzil.txt

   Comments/Improvements appreciated.

Thanks,
John