Server Virtualization is a technology that allows a physical computer to host multiple servers simultaneously. It solves a problem that has been plaguing hosting companies for some time. Previously, they had two choices; they could host shared servers or private servers. A shared server is a single computer playing host to multiple clients. Each client receives a certain percentage of the server’s memory and processing power. Private servers allocate an entire server to a single client, but the price for the client is higher. The hosting company cannot spread the maintenance costs between multiple clients. Server virtualization solves this problem.
The Internet is a network of powerful computers called servers. A server stores webpages and digital data, sending copies of its pages to the Internet browsers who request them. These servers are run by special operating systems that organize and process the massive amounts of information flowing through them daily. Servers are stored in special locations called data centers. A data center is a secured facility built for the express purpose of housing and maintaining a collection of servers. Tremendous amounts of heat are generated by this server equipment and it also uses great volumes of electricity.
Server virtualization is a great boon to Internet hosting companies and data centers alike. By virtualizing a server environment, a single physical computer can play host to multiple virtual servers. Each virtual server has its own operating system and shares the physical machine’s memory and processing power with the others. In theory, virtualization could create enough servers to use all of the machine’s processing power. In practice, this is considered dangerous and is never done.
Virtualizing a server environment is by no means a new idea. Computer scientists have been creating virtual servers on supercomputers for decades. Technological progress finally made the technique feasible for ordinary commercial and personal servers only recently. The relative youth of the technique has resulted in multiple virtualization avenues, and different companies are pioneering a plethora of approaches.
The main advantage of server virtualization is efficiency. Using one machine to simulate multiple servers saves time, energy and money. Less heat is generated and less electricity is used. Virtualization allows data centers to consolidate their server inventories and liquidate old or unnecessary equipment. Companies in data-intensive industries with thousands of servers can decrease their physical space requirements significantly. This saves money and increases profitability.
Multiple virtualization methods exist. This is a result of having different methods to actually virtualize a physical server. Some of the most common involve partitioning system resources into separate units. This can be done at the hardware or software level. Which level is chosen depends on the overall utilization of server resources. As more clients use the same physical machine, the memory and processing resources approach their maximum capacities. A partition at the software level often experiences problems when this happens.
A better method in this scenario is to create partitions at the hardware level. Each partition has its own operating system and uses processing power and memory assigned to it by a service processor. Hardware partitions can be run statically or dynamically. A static partition cannot be adjusted when the system is in use. The specific operating system must be rebooted for any changes to take effect. A dynamic partition is much more serviceable. Changes go into effect without needing to restart the system. Resources can be added, subtracted or replaced without any hassle.
Despite the advantages of server virtualization , significant downsides exist. Virtualization splits the physical machine’s processing power and gives a portion to each simulated server. Clients with high-demand needs can slow down or even crash the machine, rendering all the virtual servers inaccessible.