Two-node Cluster with Unified Nodes¶
In order to achieve Geo-Redundancy using the Unified nodes, you need the consider the following:
Two unified nodes - each node combining application and database roles - are clustered and optionally split over two geographically disparate locations.
(Optional) Two web proxy nodes can be used. It may be omitted if an external load balancer is available.
Web proxy and unified nodes can be contained in separate firewalled networks.
Database synchronization takes place from primary to secondary unified nodes, thereby offering Disaster Recovery if the primary node fails.
If the secondary unified node has more than 10ms latency with the primary unified node, it must be configured to be in the same geographical location.
Important
With only two Unified nodes, with or without Web proxies, there is no High Availability. The database on the primary node is read/write, while the database on the secondary is read only.
Only redundancy is available.
If the primary node fails, a manual delete of the primary node on the secondary and a cluster provision will be needed.
If the secondary node fails, it needs to be replaced.
Refer to the topic on DR Failover and Recovery in a 2 Node Cluster in the Platform Guide.
The diagram below illustrates the two node cluster:
