Tier 3 and Tier 4 data centers in the Netherlands explained: what is the difference?
Data center Tiers indicate the guarantees and redundancy of a data center. The higher the classification, the better the data center's availability. In this article, we explain which data center Tiers exist and what the differences are.
To assess the availability of a data center, the American TIA-942 standard was established in 2005 by the Uptime Institute. It classifies data centers into four levels: Tier 1 (Basic capacity), Tier 2 (Redundancy of major components), Tier 3 (Concurrently maintainable), and Tier 4 (Fault tolerant). These Tiers indicate the guarantees and redundancy. The higher the classification, the better the data center's availability. Each Tier builds upon the previous one: Tier 4 includes all components of Tier 1, Tier 2, and Tier 3, plus several additional requirements.
The four different Tiers
Tier 1 This is the simplest configuration and the baseline that every data center must meet. There is one power supplier, one UPS (Uninterruptible Power Supply), and one power feed to the components. There is no redundancy. Any planned or unplanned outage will lead to downtime.
Tier 2 Tier 2 is slightly more comprehensive. It features one power supplier, one backup generator, one UPS, and one power feed to the components. In the event of a power failure, the generator can be used. However, not all components are redundant, meaning downtime still occurs during maintenance or outages.
Tier 3 Tier 3 offers redundancy for installations and components. There are two power suppliers, two backup generators, two UPS units, and two power feeds to the components. Only one path is active at any given time. During maintenance or an outage, the other path becomes active, ensuring no impact on availability.
Tier 4 Tier 4 provides full redundancy. There are two power suppliers, two backup generators, two UPS units, and two power feeds to the components. The major difference from Tier 3 is that in Tier 4, both paths provide half the power. In the event of an outage or maintenance, the other path provides the total power.
Tier classifications in Dutch data centers
Tier classifications are based on American standards. Dutch data centers are structured differently, making classification more complex. Tier 1 and Tier 2 are easy to achieve in the Netherlands. Since 99.99% availability is possible in the Netherlands, Tier 3 data centers are also present. Tier 4 data centers do not exist in the Netherlands because Tier 4 requires power to be delivered via two completely separate paths. In the Netherlands, we have a single power grid infrastructure, making this impossible.
What is a Tier 3+ data center?
Fundaments works exclusively from Tier 3+ data centers. A Tier 3+ data center is currently the highest achievable class for a Dutch data center. Such a facility covers every aspect of security, including guaranteed power supply, intrusion protection, water and fire detection, and climate control.
All these components must be fully implemented. Regarding security, this means checks start at the gate: unregistered visitors must undergo a registration and authorization procedure. Access is impossible without approval from a Fundaments-authorized person. Furthermore, it must be clear at all times who is entering the data center, when, and where. This must be monitored 24/7, which is why we always require local security with a manned reception desk. Additionally, multiple access factors are used, such as fingerprints, iris scans, or hand scans.
Beyond security, the crucial factors for hardware performance must also be in order. Take power, for example. In addition to using at least two different power feeds, these must be uniquely protected with UPS systems. This is to absorb power spikes and provide stable power. Furthermore, sufficient generator capacity must be available via diesel generators in case of a power supply failure.
The final component regarding quality is climate. Cooling must be in order; temperature does not necessarily need to be low, but it must be stable. There is more: humidity must be accurately measured and stable. When this is well-monitored, the risk of the greatest nightmare—fire—is well-managed. Fundaments' Tier 3+ data centers use sensors that measure air composition locally; if levels indicate a short circuit or an incipient fire, a potential catastrophe can be quickly detected and mitigated. Fire suppression is also important; using argon gas, oxygen levels in a data hall can be lowered rapidly to extinguish a fire. This measure is a last resort but ensures the infrastructure remains undamaged.
As described, many components determine a data center's quality. Fundaments adds its own quality metric to its requirements list: data center efficiency, expressed as the PUE (Power Usage Efficiency) value. This value indicates how much energy is required to operate the data center.
