failover and loadbalance for relayed requests

[Leandro]

Hi dhcp users:
I have a few years working with isc dhcp, I would like to move my dhcp 
service scheme to a virtualized enviroment to provide HA and load 
balance on a relayed scheme.
I would like to ask for some documentation to read and also ask for the 
dhcp isc failover capabilities and recommendations.
I imagine to setup two servers for instance with lease database sync and 
two ips configured on the relays ... is that possible ? how does iscp 
manage the leases db sync?
also could think in a proxy or a load balancer but need to investigate 
and read a little bit more about it ....
Ok  ... that`s all ... any idea would be wellcome,
Regards,
Leandro.