Data Center Tiers: Everything You Need to Know

Data center tiers are the Uptime Institute’s classification system of data center performance. Created over 25 years ago, there are four data center tiers that are the established standards in categorizing the performance level of a data center.

To be classified as a specific tier, there is a set of criteria that data centers must meet, and the key values of those tier standards are service availability, redundancy level, power and cooling infrastructure, operational sustainability, security, and carrier neutrality. Data centers are ranked from one to four, with one being the lowest-performing and four being the highest. The tiers are progressive, meaning that each new tier must meet the requirements of the tiers below.

Data centers can request an evaluation to receive a certification from the Uptime Institute. This certification can lead to more credibility, increased trust with current and potential customers, and awareness of the facility’s capabilities.

What Are the 4 Data Center Tiers?

Tier 1. A Tier 1 data center is considered the lowest certification in the Uptime Institute’s classification of data center performance. This tier has the infrastructure to provide the power and cooling capacity that is required to fully support the IT load. It is specifically targeted to small businesses looking for a cost-effective solution that don’t have the requirements or budgets for Tier 2, Tier 3, or Tier 4 data centers. As the most basic tier, tier 1 data centers achieve the following:

• Meet basic capacity and infrastructure requirements. Tier 1 facilities may be in an office setting and may include an uninterruptible power supply (UPS), a designated area for IT systems, dedicated cooling equipment, and a generator.
• No redundancy. Tier 1 facilities may help protect from downtime caused by human error, but maintenance and repairs require a complete operations shutdown.
• No more than 28.8 hours of downtime per year. Users can expect downtime due to the lack of backup infrastructure in a Tier 1 facility, but 28.8 hours is the maximum amount of downtime allowed for maintenance and emergencies.
• 99.671% uptime. This is the least amount of uptime that a facility certified by Uptime Institute can guarantee.

Tier 2. A Tier 2 data center is the second-lowest certification in Uptime Institute’s system. Like Tier 1, Tier 2 data centers also rely on a single distribution path for cooling and power, making these facilities still vulnerable to unexpected disruptions. Small- and medium-sized businesses often use this level as there are more guarantees of efficiency and redundancy than Tier 1, but significantly lower costs than higher tiers due to offering less redundancy and no protection from outages. In addition to meeting the requirements of Tier 1 data centers, Tier 2 facilities must achieve the following:

• Partial power and cooling redundancy. While there is not the N+1 or 2N+1 redundancy that Tier 3 and Tier 4 providers guarantee, there are some redundant components in place to help prevent downtime.
• No more than 22 hours of downtime per year. This is the maximum amount of downtime allowed in a year for maintenance and emergencies.
• 99.741% uptime. Since no part of the system is fault-tolerant, downtime will occur in the event of an unexpected outage.

Tier 3. A Tier 3 data center is Uptime Institute’s second-highest certification. Tier 3 facilities are very manageable and have multiple distribution paths for cooling and power. Different from Tier 1 and Tier 2 data centers, Tier 3 data centers do not require a complete shutdown for maintenance and equipment repairs. This classification is the most common certification given by Uptime Institute and is often utilized by organizations larger than a typical small- to medium-sized business. This tier also provides many of the offerings that Tier 4 provides but guarantees slightly less uptime and is not completely fault tolerant. In addition to meeting the requirements of Tier 1 and Tier 2 data centers, Tier 3 data centers must achieve the following:

• N+1 redundancy. Tier 3 data centers provide N+1 redundant power and cooling distribution paths to allow for routine maintenance without downtime. 
• 72-hour outage protection. Three days of independent power that is not connected to any outside source is required.
• No more than 1.6 hours of downtime per year. This is the maximum amount of downtime allowed in a year for maintenance and emergencies.
• 99.982% uptime. Some downtime may occur for unplanned maintenance and emergencies. Customer-facing services may be impacted.

Tier 4. Tier 4 is the highest certification by Uptime Institute. This tier provides enterprise-level service for mission-critical infrastructure and ensures that equipment will continue to operate safely in the event of any mechanical failure. Full redundancy and fault tolerance mitigate the risk of downtime and high levels of security offer protection. The temperature and humidity in the environment are consistently kept in the optimal ranges to provide maximum efficiency and extend the lifecycle of hardware. Tier 4 facilities also have multiple physically isolated systems that behave as redundant components and distribution paths. As the most expensive tier, Tier 4 customers are typically international organizations with an extreme service demand. In addition to meeting the requirements of Tier 1, Tier 2, and Tier 3 data centers, Tier 4 data centers must achieve the following:

• 2N+1 redundancy. Tier 4 data centers are fully redundant with double the amount of distribution paths needed plus a backup.
• 96-hour outage protection. Four days of independent power that is not connected to any outside source is required.
• No more than 0.5 hours of downtime per year. Within Tier 4 data centers, customers do not experience any more than 26.3 minutes of downtime each year.
• 99.995% uptime. This is the highest uptime guarantee.
• No single points of failure. Since every process is fully redundant, no single outage will shut the entire system down.
• All IT equipment follows a fault-tolerant power design. When a piece of equipment fails or there is an interruption in a distribution path, IT operations are not impacted.
• Continuous cooling to maintain safe operating environment. The environment is maintained at an ideal temperature to increase efficiency and extend the useful life of hardware.

What is a Tier 5 Data Center?

A Tier 5 data center is a relatively new standard of data center requirements and meets all the criteria for a Tier 4 data center in addition to a few new ones. While Uptime Institute has not officially defined Tier 5, the data center provider Switch announced in 2017 their criteria for this new data center tier. After continuously receiving Tier 4 Gold certifications from Uptime Institute, Switch decided to raise the bar and create Tier 5 Platinum standards. This new tier is expected to be the most extensive standard and aims to increase the transparency and quality of data center rating principles.

Switch is determined to utilize the Tier 5 standard to create the new Data Center Standards Foundation (DCSF) and work in contrast to Uptime Institute. This new criterion is supposedly more thorough and aggressive than Uptime Institute’s four-tier rating framework.

Tier 5 meets all the previous tiers’ criteria, but Switch’s Tier 5 Platinum additionally requires:

• A & B power stays online during 90% of site maintenance
• Stored energy system configured with N+1 redundancy
• Stored energy system has a permanently installed monitor
• Critical distribution path equipped with features to provide circuit monitoring from UPS to power panel branch circuits
• Multiple stations at three separate functioning locations control and monitor facility for standby generation power
• Multiple fully-functional stations within the electrical backbone for switchgear control and monitoring at three separate locations
• Able to run forever without water
• Outside air pollutant detection and protective response capabilities

For a full list of the new criteria requirements for Tier 5 that Switch has announced, click here.

Switch’s Tier 5 Platinum standard evaluates more than 30 extra key elements such as sustainability, internet, connectivity, and physical security. This standard also guarantees that a data center’s power and cooling systems are fault sustainable in design, implementation, and operation.

What Are the Benefits of Having a Tier Certified Data Center?

An official certification from Uptime Institute can increase credibility and trust with current and prospective customers. Uptime Institute has issued over 2,500 certifications across the world and continues to be recognized as a global standard for data center reliability and overall performance.

The main benefits of having a certified data center by Uptime Institute are that it:

• Shows investors, clients, and the industry that your data center can meet the highest standards for IT functionality and capacity
• Validates that your system design is consistent with your uptime objective
• Ensures that your organization’s capital investments yield desired results
• Shows that your company has action plans in place to minimize unplanned downtime and unnecessary spending
• Proves to parties involved that your strategy is clearly defined and passes thorough assessments from industry experts

How Do You Get Your Data Center Tier Certified?

In order to receive a tier certification, you must contact the Uptime Institute and go through the Tier Certification program.

Uptime Institute is the only licensed firm that ultimately measures your data center’s capability and performance to award tier certifications that can show investors and clients that you are able to meet specific expectations.

The exact method of how Uptime Institute assigns data center tier certifications is mostly kept private, but there are key metrics available to the public that they base their consideration on. They look at the services available and the amount of uptime guaranteed, redundancy levels and the state of your cooling and power systems, and protocols and sustainability measures in place.

Which Data Center Tier is Right For You?

Determining which data center tier is right for your organization will depend on several factors and can be extensive. Higher tiers offer more reliable services, but they are also more expensive and not always the right fit for your company.

When considering which tier you should consider for your data center deployment, you should primarily look at cost and uptime. It is important to know how much downtime you can accept and select the appropriate tier so that you aren’t paying for a higher tier that does not align with your organization’s requirements. You can start out at a lower tier and work your way up, though there are risks and costs associated with moving your data center.

If you have a larger data center with more capacity and redundancy needs, the lower tier standards might not offer the right services and full protection whereas higher tiers can. If your focus is on efficiency, Tier 3 is the lowest tier that will provide your organization the services needed without having concerns about downtime that occurs in lower tiers. If you are seeking total protection, financial stability, and essentially no downtime, Tier 4 and higher is where your company should aim.

Overall, tier certifications from Uptime Institute help indicate a data center’s overall performance and reliability which can help tenants select a colocation provider and help data centers demonstrate their credibility.

How to Ensure Redundancy with DCIM Software

Redundancy and uptime are some of the most significant factors in determining the tier of a data center. If ensuring data center redundancy is important to you, Data Center Infrastructure Management (DCIM) software is a must-have.

DCIM software enables you to run a failover simulation report to identify which cabinets are at risk and what equipment will continue functioning in the event a PDU goes down. You can decrease the likelihood, severity, and duration of an outage by continuously polling intelligent rack PDUs to ensure they are online and have accurate documentation to quickly troubleshoot issues. By following proper data center monitoring and management best practices with DCIM software, you may require less redundancy than originally estimated, decreasing costs. 

Want to see how Sunbird’s second-generation DCIM software can dramatically simplify data center management for any tier? Get your free test drive now.