Server farm
Encyclopedia
A server farm or server cluster is a collection of computer servers usually maintained by an enterprise
Business
A business is an organization engaged in the trade of goods, services, or both to consumers. Businesses are predominant in capitalist economies, where most of them are privately owned and administered to earn profit to increase the wealth of their owners. Businesses may also be not-for-profit...

 to accomplish server needs far beyond the capability of one machine. Server farms often have backup servers, which can take over the function of primary servers in the event of a primary server failure. Server farms are typically co-located with the network switch
Network switch
A network switch or switching hub is a computer networking device that connects network segments.The term commonly refers to a multi-port network bridge that processes and routes data at the data link layer of the OSI model...

es and/or routers which enable communication between the different parts of the cluster and the users of the cluster. The computers, routers, power supplies, and related electronics are typically mounted on 19-inch rack
19-inch rack
A 19-inch rack is a standardized frame or enclosure for mounting multiple equipment modules. Each module has a front panel that is wide, including edges or ears that protrude on each side which allow the module to be fastened to the rack frame with screws.-Overview and history:Equipment designed...

s in a server room
Server room
A server room is a room that houses mainly computer servers. In information technology circles, the term is generally used for smaller arrangements of servers; larger groups of servers are housed in data centers...

 or data center
Data center
A data center is a facility used to house computer systems and associated components, such as telecommunications and storage systems...

.

Applications

Server farms are commonly used for cluster computing
Cluster Computing
Cluster Computing: the Journal of Networks, Software Tools and Applications is a journal for parallel processing, distributed computing systems, and computer communication networks....

. Many modern supercomputer
Supercomputer
A supercomputer is a computer at the frontline of current processing capacity, particularly speed of calculation.Supercomputers are used for highly calculation-intensive tasks such as problems including quantum physics, weather forecasting, climate research, molecular modeling A supercomputer is a...

s comprise giant server farms of high-speed processors connected by either Gigabit Ethernet
Gigabit Ethernet
Gigabit Ethernet is a term describing various technologies for transmitting Ethernet frames at a rate of a gigabit per second , as defined by the IEEE 802.3-2008 standard. It came into use beginning in 1999, gradually supplanting Fast Ethernet in wired local networks where it performed...

 or custom interconnects such as Infiniband
InfiniBand
InfiniBand is a switched fabric communications link used in high-performance computing and enterprise data centers. Its features include high throughput, low latency, quality of service and failover, and it is designed to be scalable...

 or Myrinet
Myrinet
Myrinet, ANSI/VITA 26-1998, is a high-speed local area networking system designed by Myricom to be used as an interconnect between multiple machines to form computer clusters. Myrinet has much lower protocol overhead than standards such as Ethernet, and therefore provides better throughput, less...

. Web hosting is a common use of a server farm; such a system is sometimes collectively referred to as a web farm. Other uses of server farms include scientific simulations (such as computational fluid dynamics
Computational fluid dynamics
Computational fluid dynamics, usually abbreviated as CFD, is a branch of fluid mechanics that uses numerical methods and algorithms to solve and analyze problems that involve fluid flows. Computers are used to perform the calculations required to simulate the interaction of liquids and gases with...

) and the rendering of 3D computer generated imagery
3D rendering
3D rendering is the 3D computer graphics process of automatically converting 3D wire frame models into 2D images with 3D photorealistic effects on a computer.-Rendering methods:...

 (also see render farm
Render farm
A render farm is a computer cluster built to render computer-generated imagery , typically for film and television visual effects, using off-line batch processing. This is different from a render wall, which is a networked, tiled display used for real-time rendering...

).

Server farms are increasingly being used instead of or in addition to mainframe computer
Mainframe computer
Mainframes are powerful computers used primarily by corporate and governmental organizations for critical applications, bulk data processing such as census, industry and consumer statistics, enterprise resource planning, and financial transaction processing.The term originally referred to the...

s by large enterprises, although server farms do not yet reach the same reliability levels as mainframes. Because of the sheer number of computers in large server farms, the failure of individual machines is a commonplace event, and the management of large server farms needs to take this into account, by providing support for redundancy
Redundancy (engineering)
In engineering, redundancy is the duplication of critical components or functions of a system with the intention of increasing reliability of the system, usually in the case of a backup or fail-safe....

, automatic failover
Failover
In computing, failover is automatic switching to a redundant or standby computer server, system, or network upon the failure or abnormal termination of the previously active application, server, system, or network...

, and rapid reconfiguration of the server cluster.

Performance

The performance of the very largest server
Server (computing)
In the context of client-server architecture, a server is a computer program running to serve the requests of other programs, the "clients". Thus, the "server" performs some computational task on behalf of "clients"...

 farms (thousands of processors and up) is typically limited by the performance of the data center
Data center
A data center is a facility used to house computer systems and associated components, such as telecommunications and storage systems...

's cooling
Computer cooling
Computer cooling is required to remove the waste heat produced by computer components, to keep components within their safe operating temperature limits.Various cooling methods help to improve processor performance or reduce the noise of cooling fans....

 systems and the total electricity cost rather than by the performance of the processors. Computers in server farms run 24/7, and consume much electricity. For this reason, the critical design parameter for both large and continuous systems tends to be performance per watt
Performance per watt
In computing, performance per watt is a measure of the energy efficiency of a particular computer architecture or computer hardware. Literally, it measures the rate of computation that can be delivered by a computer for every watt of power consumed....

, rather than cost of peak performance or (peak performance / (unit * initial cost)). Also, for high availability
High availability
High availability is a system design approach and associated service implementation that ensures a prearranged level of operational performance will be met during a contractual measurement period....

 systems that must run 24/7 (unlike supercomputers that can be power-cycled to demand, and also tend to run at much higher utilizations), there is more attention placed on power saving features such as variable clock-speed
Clock rate
The clock rate typically refers to the frequency that a CPU is running at.For example, a crystal oscillator frequency reference typically is synonymous with a fixed sinusoidal waveform, a clock rate is that frequency reference translated by electronic circuitry into a corresponding square wave...

 and the ability to turn off both computer parts, processor parts, and entire computers (WoL
Wake-on-LAN
Wake-on-LAN is an Ethernet computer networking standard that allows a computer to be turned on or woken up by a network message....

 and virtualization) according to demand without bringing down services.

Performance per watt

The EEMBC
EEMBC
EEMBC, the Embedded Microprocessor Benchmark Consortium, is a non-profit organization formed in 1997 with the aim of developing meaningful performance benchmarks for the hardware and software used in embedded systems...

 EnergyBench, SPECpower
SPECpower
SPECpower_ssj2008 is the first industry-standard benchmark that evaluates the power and performance characteristics of volume server class computers. It is available from the Standard Performance Evaluation Corporation . SPECpower_ssj2008 is SPEC's first attempt at defining server power measurement...

, and the Transaction Processing Performance Council
Transaction Processing Performance Council
Transaction Processing Performance Council is a non-profit organization founded in 1988 to define transaction processing and database benchmarks and to disseminate objective, verifiable TPC performance data to the industry...

 TPC-Energy are benchmarks designed to predict performance per watt in a server farm. The power used by each rack of equipment can be measured at the power distribution unit
Power distribution unit
A power distribution unit is a device fitted with multiple outputs designed to distribute electric power, especially to racks of computers and networking equipment located within a data center....

.
Some servers include power tracking hardware so the people running the server farm can measure the power used by each server. The power used by the entire server farm may be reported in terms of power usage effectiveness
Power usage effectiveness
Power usage effectiveness is a measure of how efficiently a computer data center uses its power; specifically, how much of the power is actually used by the computing equipment ....

 or data center infrastructure efficiency
Data center infrastructure efficiency
Data center infrastructure efficiency , is a performance improvement metric used to calculate the energy efficiency of a data center...

.

According to some estimates, for every 100 watts spent on running the servers, roughly another 50 watts is needed to cool them. Iceland
Iceland
Iceland , described as the Republic of Iceland, is a Nordic and European island country in the North Atlantic Ocean, on the Mid-Atlantic Ridge. Iceland also refers to the main island of the country, which contains almost all the population and almost all the land area. The country has a population...

, which has a cold climate all year as well as cheap and carbon-neutral geothermal electricity
Geothermal electricity
Geothermal electricity is electricity generated from geothermal energy.Technologies in use include dry steam power plants, flash steam power plants and binary cycle power plants...

 supply, is building its first site. Fibre optic cables are being laid from Iceland to North America
North America
North America is a continent wholly within the Northern Hemisphere and almost wholly within the Western Hemisphere. It is also considered a northern subcontinent of the Americas...

 and Europe
Europe
Europe is, by convention, one of the world's seven continents. Comprising the westernmost peninsula of Eurasia, Europe is generally 'divided' from Asia to its east by the watershed divides of the Ural and Caucasus Mountains, the Ural River, the Caspian and Black Seas, and the waterways connecting...

 to enable companies there to locate their servers in Iceland.

Siting is one of the factors that affect the energy consumption and environmental effects of a server farm. In areas where climate favors cooling and lots of renewable electricity is available the environmental effects will be more moderate. Thus countries with favorable conditions, such as Canada, Finland, Sweden and Switzerland, are trying to attract cloud computing data centers.

Heat from the servers can be used to help heat buildings in cold climates, thus reducing the energy consumption of conventional heaters.

See also

  • Blade server
    Blade server
    A blade server is a stripped down server computer with a modular design optimized to minimize the use of physical space and energy. Whereas a standard rack-mount server can function with a power cord and network cable, blade servers have many components removed to save space, minimize power...

  • Compile farm
    Compile farm
    A compile farm is a server farm, a collection of one or more servers, which has been set up to compile computer programs remotely for various reasons...

  • Data center
    Data center
    A data center is a facility used to house computer systems and associated components, such as telecommunications and storage systems...

  • Green computing
    Green computing
    Green computing or green IT, refers to environmentally sustainable computing or IT. In the article Harnessing Green IT: Principles and Practices, San Murugesan defines the field of green computing as "the study and practice of designing, manufacturing, using, and disposing of computers, servers,...

  • Render farm
    Render farm
    A render farm is a computer cluster built to render computer-generated imagery , typically for film and television visual effects, using off-line batch processing. This is different from a render wall, which is a networked, tiled display used for real-time rendering...


External links

The source of this article is wikipedia, the free encyclopedia.  The text of this article is licensed under the GFDL.
 
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