The following diagram depicts the Disaster Recovery and High Availability scenario for a Tier 1 service agreement level, as implemented by VLPARtm automated deployment. Under this scenario, four(4) nodes are created across two datacenters, two nodes in each datacenter.
In this scenario, both datacenters are considered to be running production business functions. These functions normally run on a single node in one of the datacenters, with a hot-standby node providing high availability fail-over capabilities. Periodically, for maintenance and disaster recovery testing, the business function load is shifted from one datacenter to the other. Once the business functions are running in the other datacenter, it is not failed-back until the next scheduled maintenance or an unscheduled outage to the datacenter occurs.