VN 
Virtualization is a technology that allows to create several independent machines from one physical machine. Each virtual machine is a separate system with its own applications & operating systems.
Two methods of Virtualization:
• Virtualization Management Layer: Virtualization is performed on the existing OS by using software like Microsoft’s Virtual PC, Vmware’s Workstation or Virtual Box,etc.
• Dedicated Virtualization:Virtualization is performed on the server hardware, taking resources directly from server. It is a more optimal & higher performance solution than the other method. Popular software products are Vmware’s ESX, Citrix’s Xen Server or Microsoft’s Hyper-V.
Limitation of traditional solutions:
• High cost: More hardware are required, higher cost for hardware procurement, more electricity for power supply and cooling, more space for hardware storage.
• Low investment efficiency: For each server designed for one specific application, CPU’s actual usage is only around 5-15% of its capacity
• Low management capability: It is hard to manage and monitor a complicated environment with many different servers, applications, OS.
• Low Productivity: IT manager will need more time to install, configure, maintain servers, little time is set for other activities, projects that helps upgrade or improve IT system.
Benefits of Virtualization
Virtualization reduces IT cost, optimizes servers’ operation with up to 50% reduction in hardware procurement and operational cost. Virtualization also makes it faster to install, configure servers and automates the management of server resources such as:
• Simplify infrastructure management with central management.
• With automation management of server resources, IT personnel have more time to focus on managing applications and services that bring more benefits to users and organization.
• Up to 50% cost reduction in acquiring new hardware and associated costs by optimizing the efficiency of current servers.
• High availability
+ No system downtime during normal maintenance, hardware upgrade, OS patch updates, firmware.
+ Ability to auto restart when there’s a problem.
+ Reduce system downtime during system maintenance, hardware upgrade, hardware relocation…with no effect to applications, services running on servers, allowing virtualized machine to move easily between servers.
• Quick Recovery: With virtualization, recovery or implementation time are shortened considerably since system resources are easily copied or cloned.
