Information Technology Reference
In-Depth Information
Servers
A
server
is a computer used by many users to perform a specific task, such as running network
or Internet applications. Servers typically have large memory and storage capacities, along
with fast and efficient communications abilities. A Web server handles Internet traffic and
communications. An Internet caching server stores Web sites that a company uses frequently.
An enterprise server stores and provides access to programs that meet the needs of an entire
organization. A file server stores and coordinates program and data files. A transaction server
processes business transactions. Server systems consist of multiuser computers, including
supercomputers, mainframes, and other servers. Often an organization will house a large
number of servers in the same room where access to the machines can be controlled and
authorized support personnel can more easily manage and maintain them from this single
location. Such a facility is called a
server farm
.
Servers offer great
scalability
, the ability to increase the processing capability of a com-
puter system so that it can handle more users, more data, or more transactions in a given
period. Scalability is increased by adding more, or more powerful, processors.
Scaling up
adds
more powerful processors, and
scaling out
adds many more equal (or even less powerful)
processors to increase the total data-processing capacity.
A virtual server is a method of logically dividing the resources of a single physical server
to create multiple logical servers, with each acting as if it is running on its own dedicated
machine. Often a single physical Web server is divided into two virtual private servers. One
of the virtual servers hosts the live Web site while the other hosts a copy of the Web site. The
second private virtual server is used to test and verify updates to software before changes are
made to the live Web site. The U.S. Marine Corps has adopted server virtualization to reduce
the number of its data centers from 300 to 30 plus 100 mobile platforms. They will do this
by setting up virtual servers capable of running half a dozen or so applications, eliminating
the need to dedicate one server to one application.
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A
blade server
houses many computer motherboards that include one or more processors,
computer memory, computer storage, and computer network connections. These all share a
common power supply and air-cooling source within a single chassis. By placing many blades
into a single chassis, and then mounting multiple chassis in a single rack, the blade server is
more powerful but less expensive than traditional systems based on mainframes or server
farms of individual computers. In addition, the blade server approach requires much less
physical space than traditional server farms.
The city of Burbank, California upgraded to IBM blade servers to provide the speed and
flexibility it needed in its computer hardware. The servers run an Oracle ERP system and a
geographic information system that maps the city's infrastructure of streets, gas and power
lines, and sewers. Converting to new blade servers from a collection of different stand-alone
computers and regular servers reduced the total cost of ownership by 40 percent and made
the Information Systems @ Work special feature to learn about another interesting use of
blade server technology.
server
A computer designed for a specific
task, such as network or Internet
applications.
scalability
The ability to increase the capability
of a computer system to process
more transactions in a given period
by adding more, or more powerful,
processors.
blade server
A server that houses many
individual computer motherboards
that include one or more proces-
sors, computer memory, computer
storage, and computer network
connections.
The Dell Power Edge 1855 Chassis
can hold up to ten blade servers.
(Source: Courtesy of Dell Inc.)
