Virtualization technologies date back to IBM Mainframes in the 1970s. From that time, virtualization has been used to run multiple, separate processes on the same hardware. A virtualized environment consists of one or more virtual machines (VMs), in which multiple guest operating systems reside and run one or more applications simultaneously. The physical hardware on which the virtualization is done is called the host. The host CPU is manufactured with advanced hardware features so as to be compatible with the virtualization software. The current AMD Opteron family of CPUs and Intel Xeon family of CPUs has advanced hardware features needed for virtualization. The host operating system runs the virtualization software, which is called Virtual Machine Monitor (VMM). This software can either be a special firmware concerned only with virtualization, or the operating system itself can do the job if it supports virtualization. The former is termed type 1 virtualization or type 1 hypervisor while the latter is known as type 2.
Virtualization is primarily intended to increase server utilization, which translates to reduced expenses for server deployment, server maintenance, IT center floor space and cooling systems.
VMware is the market leader in virtualization software for x86. ESX 3.5 being the most common x 86 virtualization platforms. Hyper-V is Microsoft’s virtualization layer, and is simply a feature of Windows Server 2008.
Virtualization technologies have revolutionized DR systems. Virtualization deployed as a feature of online backup service can reduce the amount of hardware required and simplify recovery operations. Implementing a disaster recovery solution can be simplified using virtual technologies and result in a much lower overall cost. In the past, it has been expensive to get one server to replicate to the other because those two servers had to be basically identical. In order for them to be identical, the same hardware was needed in both the main and backup locations. With virtualization, those hardware costs are cut down significantly because of the ability to host several machines on one server. The DR solution should be such that, each workload running on a physical server can replicate and failover to a dedicated virtual machine on a single physical server, eliminating the need to deploy and manage multiple physical servers at the recovery site. In a virtual machine at the DR solution provider’s end, a number of the client’s physical servers can be protected. The result is a very high level of application protection and availability for the clients with a much lower TCO as virtual machine solutions offer improved efficiency and lower IT costs.
