As a huge number of companies are relying on Data Centers as part of their business and digital information, the Data Center infrastructure provider must assure a certain level of security and guarantee in terms of redundancy. Keep reading and discover all the information about data center redundancy!

What is Redundancy in Data Centers

Redundancy in data centers is defined as a system design where a component is duplicated so that in the event of any power outage, equipment failure or any unexpected breakage, the IT equipment will not be affected in an alarming way. A good example could be having power redundancy in case of an outage.

The maximum tolerable period of disruption (MTPD) is decreasing because most companies are having less tolerance for their business and operations. ITIC (Information Technology Industry Council) released an annual survey explaining that 98% of companies said that 1h of downtime could cost over 100,000$.

Nueva llamada a la acción

Data Center Power Redundancy

The most evident concern for Data Centers is to avoid downtime, and that is usually the driver for data center redundancy. The approaches are, mainly, data center power redundancy, cooling redundancy and multiple telecom entrances

We can talk about Data center power redundancy when two or more utility feeds, generators, UPS systems and outlets connect to each rack.

Although it is rare, a device can fail, leaving you with an outage of service while the flow of power is interrupted. With redundant power in our Data Centers, you minimize this risk of this happening by connecting to an independent power system within the data center.

The truth is that this redundancy approach in Data Centers minimizes downtime associated with both failure and the need for maintenance.


Keep reading: Data Center Role: A Current Look


Different Levels of Redundancy

Redundancy in data centers is measured in N classifications. N means a basic measure of functionality and stands for duplicate unit (CRAH unit, diesel generator, UPS...), so an N-type design means no redundancy. It represents the infrastructure necessary to keep a data center operating at full capacity and under a specific workload. In the event of any failure, some major equipment and services would be affected.

Few data centers can be found that operate at this level and therefore the industry standard for minimum redundancy is N+1. A common design implies 1 extra unit for every 4 needed. This level of redundancy therefore ensures that for every four components in use in a data center, an additional element is added as a backup, i.e. there is a backup to fall back on in case of failure or maintenance. 

Following the classification, N+2 is a completely redundant system. It is equivalent to a data center architecture with one duplicated system and two independent distribution systems. In this case, the systems have 2 extra component units for every four units in use. That is, if one power source has a failure, the other must still supply power and accommodate the full load, thus eliminating any potential downtime due to the loss of one side of the system. Generally, this allows a data facility to support more extensive maintenance while maintaining the full workload.


Data Center TIERS and Redundancy

Redundancy is important in measuring data center reliability, performance and availability, as are many additional elements. The Uptime Institute offers a tiered classification system that certifies data centers according to four different levels: Level 1, Level 2, Level 3 and Level 4. 

Therefore, the TIER classification is a standardized methodology according to the official ANSI/TIA-942 standard: 

  • TIER I: Dedicated Infrastructure. 99.671% uptime.
  • TIER II: Redundant Infrastructure. 99.741% uptime.
  • TIER III: Fully Fault-Tolerant. 99.982% uptime.
  • TIER IV: Fully Fault-Tolerant. 99.995% uptime.



Basic data center with no redundant components. This is a suitable design for business that tolerate planned shutdown periods.


Redundant data centers (N+1). These ones include all of the TIER I capabilities and add extra redundancy for critical equipment such as power equipment (UPS, generators…) and cooling systems (HVAC, pumps and chillers).


Redundant data centers (N+1). These ones include all of the TIER I and TIER II capabilities and add extra redundancy. The equipment is connected to more than one power and cooling networks, with only one active. This is suitable for business than can’t tolerate large shutdowns due to the extremely importance of data stored.


Annual availability of 99.9995%.  Maximum annual shutdown of 52.56 min. The systems are connected to multiple power and cooling networks with multiple redundant equipment, following the 2(N+1) criteria.


It may interest you: How efficient is your data center?


Redundancy in your data center to guarantee maximum performance with Araner

Data centers are a critical part of your business and choosing the right architecture and redundancy model that meets your requirements can be a major challenge. An ineffective data center redundancy model can have devastating consequences for your business.

Therefore, it will be critical that you can rely on a trusted provider to offer you a certain level of security and assurance in terms of redundancy.

There is no right or wrong redundancy system, as it will depend on many factors. We always recommend contacting our team of professionals, who will help you find the best option and provide you with our specific recommendations according to the needs of your data center. Guarantee maximum performance with Araner!

Nueva llamada a la acción

icon-time 5 min