Data center

A data center is a facility used to house mission critical computer systems and associated components. It generally includes environmental controls (air conditioning, fire suppression, etc.), redundant/backup power supplies and high security.

Components

Physical Components

• Precision Air-conditioning
• Redundant HVAC Control Environment
• Power Distribution Unit (PDU)
• UPS and Backup Generators
• Power Grid Source
• Early Warning Fire / Smoke Detection
• Fire Suppression
• Raised Floor System
• Underfloor / Overhead Trunking System
• Closed Circuit TV (CCTV) Surveillance
• Security and Access Control
• 24-7-365 Server Operations Monitoring
• On premises security officers

Network Components

• Data centers contain a set of routers and switches that transport traffic between the servers and to the outside world. Network security elements are also usually deployed: firewalls, VPN gateways, Intrusion detection systems, etc.

Applications

• The main purpose of a data center is running the applications that handle the core business and operational data of the organization. Often these applications will be composed of multiple hosts, each running a single component. Common components of such applications are databases, file servers, application servers, and middleware.

Descriptions

Racks of telecommunications equipment in part of a data center.

A data center is a facility used for housing a large amount of electronic equipment, typically computers and communications equipment. As the name implies, a data center is usually maintained by an organization for the purpose of handling the data necessary for its operations. A bank for example may have a data center, where all its customers' account information is maintained and transactions involving this data are carried out. Practically every company that is mid-sized or larger has some kind of data center with the larger companies often having dozens of data centers. Most large cities have many purpose-built data center buildings in secure locations close to telecommunications services. Most colocation centers and Internet peering points are located in these kinds of facilities.

As data is a crucial aspect of most organizational operations, organizations tend to be very protective of their data. A data center must therefore keep high standards for assuring the integrity and functionality of its hosted computer environment. This is depicted in its physical and logical layout.

Before the dot com crash, millions of square meters of general-purpose data centers were built in the hope of filling them with servers for web hosting and application service providers. However this demand never came true.

Physical Layout

A data center can occupy one room of a building, one or more floors, or up to the whole building. Most of the equipment is often in the form of 1U servers (so-called "pizza boxes") racked up in 19 inch rack cabinets, which are usually placed in single rows forming corridors between them. This allows people access to the front and rear of each cabinet. Some equipment such as mainframe computers and storage devices are often as big as the racks themselves, and are placed alongside them.

The physical environment of the data center is usually under strict control:

• Air conditioning is used to keep the room cool, generally around 17 degrees Celsius (about 63 degrees Fahrenheit). This is crucial since electronic equipment in a confined space generates much excess heat, and tends to malfunction if cooling is not handled.
• Backup power is often available. This can include one or more uninterruptible power supplies and diesel generators located close by.
• To prevent single points of failure, all elements of the electrical systems, including backup system, are typically fully duplicated, and critical servers are connected to both the "A-side" and "B-side" power feeds.
• Data centers typically have raised flooring made up of 2 foot (600mm) removable square tiles. These provide a plenum for air to circulate below the floor, as part of the air conditioning system, as well as providing space for power cabling. Data cabling is typically routed through overhead cable trays in modern data centers.
• Data centers often have elaborate fire prevention and fire extinguishing systems. Modern data centers tend to have two kinds of fire alarm systems; a first system designed to spot the slightest sign of particles being given off by hot components, so a potential fire can be investigated and extinguished locally before it takes hold (sometimes, just by turning smoldering equipment off), and a second system designed to take full-scale action if the fire takes hold. Fire prevention and detection systems are also typically zoned, and high-quality fire-doors and other physical fire-breaks used, so that even if fires do break out they can be contained and extinguished within a small part of the facility.
• Using conventional water sprinkler systems on operational electrical equipment can do just as much damage as a fire so using it is not an option - also ordinary water and electricity don't mix well. Originally halon gas was used in the event of a fire to extinguish flames - an inert gas that pushes all the oxygen out of the room. However this has now been banned in some countries because of the danger it poses to people if they are trapped in the same room without emergency breathing oxygen supplies. More recent alternatives include Argonite and FM200, and even systems based on mists of tiny particles of ultra-pure water.
• Physical security also plays a large role with data centers. Physical access to the site is usually restricted to selected personnel. Video camera surveillance and permanent security guards are almost always present if the data center is large or contains sensitive information on any of the systems within.

Network Infrastructure

Communications in data centers today are most often based on networks running the IP protocol suite. Data centers contain a set of routers and switches that transport traffic between the servers and to the outside world. Redundancy is sometimes provided by getting the network connections from multiple vendors.

Some of the servers at the data center are used for running the basic Internet and intranet services needed by internal users in the organization: email servers, proxy servers, DNS servers, etc.

Network security elements are also usually deployed: firewalls, VPN gateways, Intrusion detection systems, etc. Also common are monitoring systems for the network and some of the applications.

Applications

The main purpose of a data center is running the applications that handle the core business and operational data of the organization. Such systems may be proprietary and developed internally by the organization, or bought from enterprise software vendors. Such common applications are ERP and CRM systems.

Often these applications will be composed of multiple hosts, each running a single component. Common components of such applications are databases, file servers, application servers, and middleware.

External links

• http://www.datacentertalk.com - Data Center Talk - Talk about data centers
• http://apdrc.soest.hawaii.edu - Asia-Pacific Data-Research Center - Invaluable resource for Climate Science
• http://www.bestpricecomputers.ltd.uk/servers/datacenter-cooling.htm Cooling the datacenter