Server room

A server room is a room, usually air-conditioned, devoted to the continuous operation of computer servers. An entire building or station devoted to this purpose is a data center.

The computers in a server rooms are usually headless systems that can be operated remotely via KVM switch or remote administration software, such as Secure Shell (ssh), VNC, and remote desktop.

Climate is one of the factors that affects the energy consumption and environmental impact of a server room. In areas where climate favors cooling and an abundance of renewable electricity, the environmental effects will be more moderate. Thus countries with favorable conditions, such as: Canada, Finland, Sweden, and Switzerland, are trying to attract more companies to site their server rooms there.

Design considerations
Building a server or computer room requires detailed attention to six main design considerations:

Location
Computer or server room location is the first consideration, before even considering the layout of the room’s contents. Most designers agree that, where possible, the computer room should not be built where one of its walls is an exterior wall of the building. Exterior walls can often be quite damp and can contain water pipes that could burst and drench the equipment. Certainly avoid exterior windows that will not only be a security risk, but also be susceptible to breakages. Also, try to avoid both the top floors and basements that may be prone to flooding or leaks in the case of roofs. If a centralised computer room is not feasible, server closets on each floor may be an option. This is where computer, network and phone equipment are housed in closets and each closet is stacked above each other on the floor that they service.

In addition to the hazards of exterior walls, designers need to evaluate any potential sources of interference in close proximity to the computer room. Check if there are radio transmitters in close proximity and also consider electrical interference from power plants or lift rooms, etc.

Other physical design considerations range from room size, door sizes and access ramps (to get equipment in and out) to cable organisation, physical security and maintenance access.

Air conditioning
Computer equipment generates heat, and is sensitive to heat, humidity, and dust, but also the need for very high resilience and failover requirements. Maintaining a stable temperature and humidity within tight tolerances is critical to IT system reliability.

In most server rooms “close control air conditioning” systems, also known as PAC (precision air conditioning) systems, are installed. These systems control temperature, humidity and particle filtration within tight tolerances 24 hours a day and can be remotely monitored. They can have built-in automatic alerts when conditions within the server room move outside defined tolerances.

Air conditioning designs for most computer or server rooms will vary depending on various design considerations, but they are generally one of two types: “up-flow” and “down-flow” configurations.

Up-flow air conditioning
This type of air conditioning draws air into the front of the air handler unit (AHU), cools the air over the heat exchanger, then distributes the cooled air out through the top or through duct work. This air conditioning configuration is well suited to retro-fitted computer rooms when raised floors are either of inadequate depth or do not exist at all.

Down-flow air conditioning
Typically, this type of air conditioning unit draws the air into the top of the air handling unit, cools the air over the heat exchanger, then distributes the air out of the bottom into the floor void. This conditioned air is then discharged into the server room via strategically placed floor grilles and onwards to equipment racks. These systems are well suited to new office buildings where the design can encompass raised floors suitable for ducting to computer racks.

Fire protection
The fire protection system's main goal should be to detect and alert of fire in the early stages, then bring fire under control without disrupting the flow of business and without threatening the personnel in the facility. Server room fire suppression technology has been around for as long as there have been server rooms. Traditionally, most computer rooms used Halon gas, but this has been shown to be environmentally unfriendly (ozone depleting) and unsafe for humans. Modern computer room use combinations of inert gases such as Nitrogen, Argon and CO2. Other solutions include clean chemical agents such as FM200 and also hypoxic air solutions that keep oxygen levels down.

Future-proofing
The demands of server rooms are constantly changing as organisations evolve and grow and as technology changes. An essential part of computer room design is future proofing so that new requirements can be accommodated with minimal effort. As computing requirements grow, so will a server room's power and cooling requirements. As a rough guide, for every additional 100kW of equipment installed, a further 30kW of energy is required to cool it. As a result, air conditioning designs will need to have scalability designed in from the outset.

The choice of racks in a server room is usually the prime factor when determining space. Many organisations use telco racks or enclosed cabinets to make the most of the space they have. Today, with servers that are one-rack-unit (1U) high and new blade servers, a single 19- or 23-inch rack can accommodate anywhere from 42 to hundreds of servers.

Redundancy
If the computer systems in a server room are mission critical, removing single points of failure may be of high importance. The level of redundancy is determined by factors such as whether the organisation can tolerate interruption whilst failover systems are activated, or must they be seamless without any business impacts. Other than computer hardware redundancy, the main consideration here is the provisioning of failover power supplies and cooling.