For a lan if you feel up to the task: http://www.drbd.org
I use it in my datacenter, and am now replicating it for clients over 10/100meg fiber for entire esx servers and some just data servers. Seems to work pretty well with little management. ~ Finally, powerful endpoint security that ISN'T a resource hog! ~ ~ <http://www.sunbeltsoftware.com/Business/VIPRE-Enterprise/> ~
