Virtual Appliances

A virtual appliance is one which subdivides the physical hardware into multiple virtual machines. Each virtual machine provides a self-contained appliance layer to the application. Virtual appliances can thus be distributed across the set of systems merely by transferring a virtual appliance image. Load balancing can be achieved between different servers with no need or requirement to physically move the appliance. The virtual image is simply transferred to the appropriate server.

Any given server can be running a widely disparate range of applications. Server loading can thus be tightly controlled by distributing tasks across physical servers. The resources can be equitably shared across the application pool. Memory utilization, disk utilization and of course processor utilization can be more accurately balanced and controlled.

By encapsulating each application in its own virtual appliance, the needs of that particular application can be tuned more precisely. Virtualization provides all of the benefits of the traditional appliance with the following additional key benefits.