Recent events such as hurricanes Katrina and Rita, the 911 event, the attack on the USS Cole, and the Northeast U.S. blackout have demonstrated our vulnerability to disasters and our need to find methods that provide some degree of tolerance for large cyberspace systems in the presence of disasters. Disaster Tolerance in computing and communications systems refers to the ability of infrastructure, software, IT systems, communications infrastructure and business or organizational processes that depend on these systems, to maintain functionality throughout the occurrence of a disaster. The goal of Disaster Tolerance is to provide an ability to continue uninterrupted operations, despite the occurrence of a disaster that would normally interrupt organizational operations; where critical business functions and technologies continue operations, as opposed to resuming them.