Multinode Cluster with Unified Nodes

In order to achieve Geo-Redundancy using the Unified nodes, you need the consider the following:

• Either four or six Unified nodes - each node combining Application and Database roles - are clustered and split over two geographically disparate locations.

• Two Web Proxy nodes to provide High Availability that ensure an Application role failure is gracefully handled. More may be added if Web Proxy nodes are required in a DMZ.

  It is strongly recommended not to allow customer end-users the same level of administrator access as the restricted groups of provider- and customer administrators. This is why Self-service web proxies as well as Administrator web proxies should be used.

  Systems with Self-service only web proxies are only recommended where the system is customer facing, but where the customer does not administer the system themselves.

• Web Proxy and Unified nodes can be contained in separate firewalled networks.

• Database synchronization takes places between all Database roles, thereby offering Disaster Recovery and High Availability.

• For 6 unified nodes, all nodes in the cluster are active. For an 8 node cluster (with latency between data centers greater than 10ms) , the 2 nodes in the DR node are passive, in other words, the voss workers 0 command has been run on the DR nodes.

Primary and fall-back Secondary Database servers can be configured manually. Refer to the Platform Guide for further details.

The diagrams in this section illustrate:

• the six node cluster
• the eight node cluster
• 2 Web Proxy nodes in a DMZ
• 4 (2 admin, 2 Self-service) Web Proxy nodes in a DMZ