Almost all core business applications—ERP, CRM, sales force automation, inventory, supply chain management—can benefit from high availability clustering. The attractive economics of Linux high availability clusters combined with the low cost of high performance RAID storage makes it possible to extend high availability to a broader set of business activities. Even email servers, for example, could be clustered for high availability in organizations where email has become a critical tool and a shutdown would be very disruptive. Similarly enterprises can benefit when domain services, directory services, security systems, e-commerce servers, and even standard file servers are clustered for high availability.