Although virtualization frees any single virtual machine from dependence on a single physical server, the collected virtual machines rely completely on a smaller number of servers. Formerly, a hardware failure threatened only one application, but in a virtualized environment a single hardware failure can threaten many applications running on different virtual machines. This document addresses the evolution of virtualization as well as the availability challenges it presents.

Topics covered include:

• How virtualization benefits high availability and business continuity
• Industry trends in virtualization
• How VMware ESX addresses high availability issues
• The benefits of combing fault tolerant servers with VMware to achieve continuous availability for mission-critical applications