Always On Bronze v4.3.8
The Always On Bronze architecture includes the following:
- Two BDR data nodes
 - One BDR witness node that doesn't hold data but is used for consensus
 - Two HARP-Proxy nodes for routing application traffic to the "lead" master
 - One barman node for backup and recovery can be onsite or offsite
 
BDR and HARP-Proxy nodes should be spread across availability zones.