Recommended Software RAID-5 on dual-amd64

[Norberto Meijome]

Hi all,
I have a dual Opteron box built with 
http://tyan.com/products/html/gt24b2891_spec.html , using 4 identical 
SATA drives. I plan to use FBSD 6 (installing beta2, cvsup to head). I 
will use gmirror to RAID-1 the boot partition, and RAID-5 for the 
remainder.

I was wondering which is the best option for software RAID5. GVinum? 
geom_raid5 (is there such thing yet?) - I'd love to use a geom-only 
solution if possible.

thanks in advance,
Beto