The need for robust high-availability solutions
The objective behind implementing a high availability solution is to provide near-continuous application availability through both planned and unplanned outages. Business-critical applications are configured into a cluster which typically involves at least two systems (or nodes); the cluster monitors the critical resources for changes that may indicate a failure, a pending failure, or a possible configuration change. The cluster is monitored for health and configuration changes that must be made consistent across the cluster. A cluster can also be configured for disaster recovery (DR) by providing clustering capabilities across geographically dispersed locations. As a best practice, IT shops conduct periodic disaster recovery tests to demonstrate compliance with corporate policy. Compliance tests can be both operationally expensive (tying up critical resource for the duration of the test) and cause business impact. Many companies simply cannot afford to have the IT operations unavailable for an extended DR test and therefore implement a cluster to simplify and shorten the test.
PowerHA SystemMirror Standard Edition and PowerHA System Mirror Enterprise Edition with Cluster Aware AIX (CAA), kernel-based health management, Graphical Management, HyperSwap and other integrated features are designed to provide a robust HA/DR environment focused on ease of implementation and ease of use.