Continuous power in a data centre – understanding the terminology

Data centre clients need continuous and reliable power to support servers, networking equipment, and other infrastructure that enables the provision of mission-critical applications and services for businesses and organisations. Any interruption or loss of power can result in significant consequences, including data loss, service disruptions, financial losses, and damage to reputation. For data centres, there’s more to ‘power’ than plugging into the grid, so those coming new to data centres can find some of the terms confusing. Let us unpick them for you….

Power redundancy refers to the implementation of backup power sources or systems to ensure continuous and uninterrupted power supply to critical equipment or infrastructure. Redundancy is essential in situations where a power outage can result in significant disruptions.

2N power refers to a redundant power configuration in which the power infrastructure is designed with two independent power paths to ensure redundancy and minimise the risk of power failure - even if one power source or power distribution unit (PDU) fails, the critical equipment remains powered and operational. It provides a robust infrastructure for applications that require continuous uptime and cannot tolerate power disruptions.

An uninterruptible power supply (UPS) system provides short-term emergency backup power in the event of any disruptions to the main electricity supply. In a 2N UPS system, two UPS systems operate in parallel to support the load, with each UPS capable of independently supplying the entire power requirement.

Critical equipment, such as servers or networking devices, is equipped with dual power supplies. Each power supply is connected to a separate PDU, ensuring that the equipment can draw power from either path.

If one power path fails, the equipment automatically switches to the alternate path without any interruption or downtime. This failover can be achieved through automatic transfer switches (ATS) or intelligent power distribution units that detect power loss and switch to the backup path.

Active/Active power distribution paths refer to a configuration in which power is distributed across multiple paths simultaneously, with each path actively providing power to the load. An Active/Active configuration includes multiple independent power sources, redundant PDUs, load balancing, and fault tolerance and redundancy to ensure continuous power availability. These provide a higher level of redundancy compared to single-path configurations, as multiple independent power sources and PDUs are actively delivering power to the load.