What is a Tier Standard? What are the Scope and Requirements of Tier Standards?
The importance of information in our age is indisputable. As information spreads and reproduces, its rapid sharing, storage and reliability gain importance. To ensure all these operations without interruption, it is necessary to keep the infrastructure established in data centers at certain levels.
Electrical, mechanical, and security systems in data centers vary according to the importance of the processed and stored data. Generally speaking, data centers include backup power supplies, redundant data communication links, climate control systems used for cooling the systems within the center, fire suppression systems, and security systems designed to protect data from external threats based on their security level. The infrastructure reliability of an established data center will reach its targeted levels through having certification of the standards. Tier standards have been created for this purpose, aiming to determine building levels based on tests and inspections conducted by independent firms.
What is Tier?
Tier is a certification by Uptime Institute that enables the classification of data centers that are extremely important and necessary today. There are 4 Tier types: Tier 1, 2, 3 and 4. Each Tier data center type has its characteristics and way of working. Companies choose a Tier data center type according to their size and needs and make their data available uninterruptedly.
What is the Tier Certification System?
Each Tier certificate represents a specific operating pattern, energy consumption, and the failure rate and planned maintenance that may occur. Some Tier certificates guarantee uninterrupted operation and data flow, while some Tier certificates are more likely to have problems with power consumption or information flow. Tier certificates specify the hardware and energy paths that data centers have. There are 4 Tier standards and requirements:
Tier 1- (Basic Capacity) Data Center Scope
Tier I certified data centers are the lowest level within the Tier standards. These data centers are primarily used by businesses that do not require extensive data storage. Unlike other data centers, equipment is housed in a room designated for this purpose within an office environment. Because these data centers do not have large operational capacities, they also do not include any backup systems. When data needs to be backed up or a change is made to the system, the hardware is stopped in a planned manner, and the system shuts down. After the system is shut down, the desired changes, repairs or upgrades are made, and the hardware is restarted in a planned manner. These data centers can experience 28.8 hours of downtime per year, so the uninterrupted operation rate is 99.676%. Tier 1 data centers are unprepared for outages longer than 10 minutes.
Tier 2 (Redundant Capacity Components) Data Center Scope
Tier II certified data centers include redundant critical power and cooling components, providing an increased safety margin against IT process interruptions due to site infrastructure equipment failures. Redundant components include uninterruptible power supply (UPS) modules, chillers or pumps, and engine generators. While components are designed with N+1 redundancy, redundancy is not expected in the distribution paths. The annual downtime for Tier II certified data centers is estimated to be 22 hours, with an uptime rate of 99.741%. These data centers can withstand 24-hour power outages thanks to their generators.
Tier 3 (Concurrently Maintainable) Data Center Scope
Tier III certified data centers feature infrastructure with redundant components and multiple independent distribution paths serving critical environments, enabling concurrent maintenance. This key differentiator means that the facility does not require any shutdowns for equipment maintenance or replacement. Tier III data centers add redundant distribution paths for power and cooling to the redundant critical components of Tier II, allowing any component required to support the IT processing environment to be shut down and maintained without affecting IT operations. These data centers have an uptime rate of 99.982% and can withstand outages of up to 72 hours.
Tier 4 (Fault Tolerant) Data Center Scope
Tier IV certified data centers have multiple independent and physically isolated systems that function as redundant capacity components and distribution paths. Zoning is required to prevent an event from compromising both systems. The environment will not be affected by a disruption caused by planned or unplanned events. However, if redundant components or distribution paths are shut down for maintenance, the environment may face a higher risk of disruption in the event of a failure.
Tier IV-certified data centers add fault tolerance to the Tier III topology. If a piece of equipment fails or there is a disruption in a distribution path, IT operations will not be affected. All IT equipment must have a fault-tolerant power design to ensure compatibility. Tier IV data centers require continuous cooling to maintain a stable environment. These data centers experience only 0.8 hours of downtime annually, achieving an uptime rate of 99.999%.