Data Centre Glossary

A specialised building or room housing computer servers, storage, and networking equipment that processes, stores, and distributes data.

A classification system (Tier I–IV) that rates a data centre’s reliability and redundancy, defined by the Uptime Institute.

A service where multiple organisations rent space (racks, cages, or private suites) in a shared data centre facility.

A massive data centre operated by a single company (like Google, Microsoft, or AWS), typically exceeding 5,000 servers and 10 MW of IT load.

The ratio of total facility power to IT equipment power. A PUE of 1.0 means all power goes to computing; the lower the better.

A contractual guarantee of availability, typically expressed as a percentage. ‘Five nines’ (99.999%) allows only 5.26 minutes of downtime per year.

A fibre optic cable laid on the ocean floor carrying intercontinental internet traffic. Seven active cables land on the Kenyan coast.

A facility where networks interconnect directly to exchange traffic locally, reducing latency and cost. Kenya’s is KIXP.

The direct interconnection of two networks to exchange traffic without a third-party intermediary, typically done at an IXP.

Processing data closer to the user or data source, rather than in a centralised data centre, to reduce latency.

A geographically distributed network of servers that delivers web content to users from the nearest location, reducing load times.

The amount of power consumed by the IT equipment (servers, storage, network) in a data centre, measured in kilowatts (kW) or megawatts (MW).

Duplication of critical components (power, cooling, network) so that a single failure does not cause an outage. Expressed as N+1, 2N, etc.

A data centre that allows tenants to choose from multiple network providers, fostering competition and preventing vendor lock-in.

A standard unit of measure for server rack height. 1U equals 44.45mm (1.75 inches). A standard full-height rack is 42U.

The time it takes for a data packet to travel from source to destination, measured in milliseconds (ms). Lower is better.

Hair-thin glass or plastic cables that transmit data as light pulses, offering far higher bandwidth and lower latency than copper.

A battery-based system that provides immediate backup power when the main grid fails, bridging the gap until generators start.