Data Center Tiers

Data Center tiers are an efficient way to describe the infrastructure components being utilized at a business’s data center. Although a Tier 4 data center is more complex than a Tier 1 data center, this does not necessarily mean it is best-suited for an organization’s needs. While investing in Tier 1 infrastructure might leave a business open to risk, Tier 4 infrastructure might be an over-investment.

Tier 4 Data Center: A Tier 4 data center is built to be completely fault tolerant and has redundancy for every component. It has an expected uptime of 99.995% (26.3 minutes of downtime annually).

Tier 3 Data Center: A Tier 3 data center has multiple paths for power and cooling and systems in place to update and maintain it without taking it offline. It has an expected uptime of 99.982% (1.6 hours of downtime annually).

Tier 2 Data Center: A Tier 2 data center has a single path for power and cooling and some redundant and backup components. It has an expected uptime of 99.741% (22 hours of downtime annually).

Tier 1 Data Center: A Tier 1 data center has a single path for power and cooling and few, if any, redundant and backup components. It has an expected uptime of 99.671% (28.8 hours of downtime annually).

Tier 4 Data Center Requirements

Zero single points of failure – Redundancies for every process and data protection stream. No single outage or error can shut down the system.
995 % uptime per annum
2N+1 infrastructure (two times the amount required for operation plus a backup) – Fully redundant
No more than 26.3 minutes of downtime per annum – Some downtime is allowed for optimized mechanical operations; however, this annual downtime does not affect user operations.
96-hour independent power outage protection – This power must not be connected to any outside source and is entirely proprietary. Some centers may have more.

Tier 4 is considered an enterprise-level service. Tier 4 has approximately twice the site infrastructure of a Tier 3 location.

If you need to host mission-critical servers, this is the level to use. Tier 4 data centers ensure the safety of your business regardless of any mechanical failures. You will have backup systems for cooling, power, data storage, and network links. Data Center Security is compartmentalized with biometric access controls. Full fault tolerance keeps any problems from ever slowing down your business. This is true even if you host less critical servers in other tier levels.

This tier also ensures optimized efficiency. Your servers are housed in the most physically advantageous locations. This drastically extends the life of your hardware. If the temperature and humidity are kept consistent, you gain a great deal of efficiency. Even the backups and dual power sources are treated like primaries.

Tier 3 Data Center Requirements

982 % uptime per annum
N+1 fault tolerance (two times the amount required for operation plus a backup) – Ability to undergo routine maintenance without a hiccup in operations. Unplanned maintenance and emergencies may cause problems that affect the system. Problems may potentially affect user-facing operations
No more than 1.6 Hours of downtime per annum – Downtime is allowed for maintenance and overwhelming emergency issues.
72 hours independent power outage protection – at least three days of exclusive power. This power cannot connect to any outside source.

Tier 3 provides most of the features of a Tier 4 infrastructure without some of the elite protections. For instance, the data center has the advantage of dual power sources and redundant cooling and the network streams are fully backed up. Guaranteed uptime is slightly less than Tier 4, and the system is not entirely fault-tolerant.

Tier 2 Data Center Requirements

741 % uptime per annum
No more than 22 Hours of downtime per annum – There is a considerable jump between levels 2 and 3 regarding downtime. Redundancy is one of the primary reasons for this.
Partial cooling and multiple power redundancies – A Tier 2 Data center will not have redundancy in all areas of operation. The most critical aspects of its mechanical structure receive priority. These two aspects are power and cooling distribution. Redundancy in these areas is only partial. No part of the system is fault tolerant.

The utility of a Tier 2 Data center is fundamentally different. If your business prioritizes redundant capacity components, then you may want to look at this level of infrastructure.

Tier 1 Data Center Requirements

671 % uptime per annum
No more than 28.8 Hours of downtime per annum – There is a considerable jump between levels 2 and 3 regarding downtime. Redundancy is one of the primary reasons for this.
Zero redundancies – A Tier 1 Data center will not have redundancy in any part of its operations. Facilities do not have any redundancy guarantees within its power and cooling certification process.

The use of the Tier I infrastructure designed for companies with a need for a colocation data center. This is the most budget conscious option for a business. The infrastructure consists of a single uplink, a single path for power, and non-redundant servers.

The tier classification system is another way of assessing redundancy and uptime reliability as you determine your organizations’ data center needs. Contact Zunesis to talk about your data center needs.

Data Center Tiers