Load sharing with enbd?

Hi all,

I'm looking into using enbd to keep two disks in sync (using enbd and
fr1) both of which need to be able to be written to.
How would this be done?  Would it be neccesary to export a disk from
machineA, and incorperate it in a raid array on machineB, and then
export the raid disk (md0 or whatever) back to machineA?  This does not
seem like a very efficient solution.  Does anyone have a better method
(or is enbd the wrong tool for this, and if so, what would be the
correct one?)  My understanding is that it is not possible to simply
export the base device from each machine, and incorperate that in a raid
array on the other machine as we would get confused data due to disk
caching.  Is this the case?  Would this be solved by mounting all
devices (including the md devices) in "sync" mode?

Thanks,
-Dan