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==Introduction==
==Introduction==


'''Our ECM file can be downloaded here:[[File: ECM_server_virtualiztion.xls]] '''
'''Our ECM file can be downloaded here:[[File: ECM_server_virtualization.xls]] '''


A Server is essentially a computer dedicated to running one or multiple server programs.  Server programs are responsible for running computer programs which require lots of memory and computing power.  Servers are connected to a network, and other computers linked to the network can access the server to run those programs.  Servers are also used to store information which can be accessed by other computers linked to the network.   
A Server is essentially a computer dedicated to running one or multiple server programs.  Server programs are responsible for running computer programs which require lots of memory and computing power.  Servers are connected to a network, and other computers linked to the network can access the server to run those programs.  Servers are also used to store information which can be accessed by other computers linked to the network.   

Revision as of 04:56, 10 February 2010

Template:425inprogress

Introduction

Our ECM file can be downloaded here:File:ECM server virtualization.xls

A Server is essentially a computer dedicated to running one or multiple server programs. Server programs are responsible for running computer programs which require lots of memory and computing power. Servers are connected to a network, and other computers linked to the network can access the server to run those programs. Servers are also used to store information which can be accessed by other computers linked to the network.

It is common practice for individual physical servers to be dedicated to running a single program or task. This ensures that there will always be enough computing power for that program, as well as eliminating any adverse complications between competing programs or tasks running on one physical server. It also makes trouble shooting an easier process when something goes wrong. That being said, often servers are extremely overpowered for running one specific program or task, and it is not uncommon for much of their computing potential to be unused.

Server virtualization, in basic terms, is a method of using this untapped server computing potential by running multiple server programs on one physical server. This is accomplished by 'tricking' the one physical server into believing it is actually multiple servers, so that there can be no unwanted interaction between programs running on the same physical server. [1]

Types of Server Virtualization

There are three main types of server virtualization. While they all essentially perform the same task, they do so in a different manner. The three types are listed below;

Virtual Machine Model - This method uses a hypervisor software which interacts with the CPU and diskspace of the server. The hypervisor acts as a platform for the virtual servers operating systems, and keeps the virtual servers unaware of each other, tricking each into thinking it is a stand alone server. The hypervisor allocates the physical servers resources to the multiple virtual server as demand changes. Each virtual server in this case runs its own operating system, and it is possible to have multiple operating systems operating on one physical server. The hypervisor however requires its own computing power, thereby 'stealing' some of the physical servers processing power.

Paravirtual Machine Model - In this model, the hypervisor is less powerful, and allows the virtual servers to be aware of each other. Some of the work done by the hypervisor in the fully virtual model is passed onto the seperate operating systems. This allows the entire physical server to act together as an integrated system and allocate the servers resources as they are required.

Virtualization at the Operating System Level - This approach fully removes the role of the hypervisor. In its place, the virtual servers run on a centralized operating system which also acts as a fully virtualized hypervisor. The servers are now aware of each other in this method and run as stand alone servers. The advantage however is that all the virtual servers are running on the same operating system, allowing for much smoother and more efficient operation of the physical server.

Benefits

The need for fewer physical servers has many benefits including:

  • Reduced physical space needed for server rooms
  • Reduced heat generation in server rooms
  • Reduced need for backup power in the event of a power failure
  • Reduced energy consumption
  • Reduced number of physical servers to purchase and maintain
  • Increased server flexibility with server migration between compatible physical servers
  • Reduced server maintenance
  • Reduced amount of complicated wiring
  • Ease of server trouble shooting
  • Reduce need for large centralized data centers

Limitations

Limitations and deterrents of server virtualization include:

  • Potential processing power deficiencies and crashed servers in high demand scenarios
  • Limited number of virtual servers on a physical server
  • Migration limitations between incompatible physical servers


Economic Costs

The cost of implementing server virtualization has a large range. The payback in terms of power savings, reduced HVAC load, and reduced physical space can be substantial. Precise costs and savings will be outlined in the ECM. There are both commercially available server virtualization options, as well as many Open Access server virtualization programs available online for free.

Server virtualization can be purchased from many companies including Novell, OPSource, NetApp, and VMware.

Citrix Systems, OpenVZ, and Xen are all examples of free open access server virtualization programs available online.

Literature Review

A full literature review was conducted prior to creating our ECM. It can be found [here]

References

  1. Wikipedia, Hardware Virtualization, http://en.wikipedia.org/wiki/Platform_virtualization
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