Mirroring: gvinum or gmirror?

[Jonathan McKeown]

I'm setting up a remote server with two identical hard drives, running 
FreeBSD-6.1. I want to set the drives up as a mirror for data redundancy. I 
also want to be able to break the mirror when I need to update the OS or 
installed software, so that if anything goes wrong with the update on one 
drive I can boot back to the other one, or if all is well, re-establish the 
mirror and synchronise to the updated system. I have serial console access 
including BIOS console redirection.

Based on web and Usenet/mailing list searches, gmirror looks more 
straightforward for this simple case, gvinum more flexible but poorly 
documented, and the most recent comments I can find (still all 6+ months ago) 
seem to suggest that gvinum hasn't completely stabilised for production yet.

Is this a fair assessment? Are there any factors I've missed? Which solution 
is likely to suit the situation better?

Jonathan