This Knowledgebase article provides information about the shared-nothing architecture.
By definition, our technology is a cluster, but unlike traditional clusters does not require shared storage. Neverfail's approach is a “shared-nothing” architecture that establishes an active/passive pair where a Primary machine is cloned to a Secondary machine.
For example, Neverfail for Exchange, which doesn’t require shared storage, cluster-aware hardware, or clustering expertise and unlike traditional clusters, doesn’t include the complexity or the cost of maintenance. Additionally, Neverfail put a lot of effort into simplifying switchback after failover, which improves the ability to return to normal state. In terms of costs, traditional clusters can be much more expensive. Microsoft clusters require Microsoft Advanced Server as an operating system, Exchange Enterprise Edition, support for other applications outside Exchange must be “cluster aware” and all included hardware must as well be “cluster aware.” These costs can add up to a significant overall total cost of ownership. Neverfail for Exchange provides cluster class availability at a fraction of the cost and complexity.