Data center tiers

There are a number of na­tion­al­ly and in­ter­na­tion­al­ly rec­og­nized standards for ensuring the quality, avail­abil­i­ty, and security of data centers. Among the most important standards are the Tier Clas­si­fi­ca­tion Standard issued by the Uptime Institute, the Telecom­mu­ni­ca­tions Industry As­so­ci­a­tion’s TIA-942 standard, DIN EN50600, and the recently in­tro­duced ISO/IEC 22237 standard. These data center tier clas­si­fi­ca­tion systems provide in­for­ma­tion about the centers’ fire safety, main­te­nance and uptime, among other things.

From your personal cloud with email and office apps to small busi­ness­es to in­ter­na­tion­al cor­po­ra­tions — pretty much everyone relies on secure data centers, cloud computing, and software-defined data centers. The more connected our social and pro­fes­sion­al worlds become, the more important it is to ensure security in data centers, prevent server failures, and maintain the avail­abil­i­ty of system resources. That’s why there are official in­ter­na­tion­al standards and clas­si­fi­ca­tions that allow you to judge a data center’s suit­abil­i­ty for your business.

There are four systems commonly used to evaluate data centers:

• Uptime Institute’s Tier Clas­si­fi­ca­tion System
• Telecom­mu­ni­ca­tions Industry As­so­ci­a­tion’s TIA-942 standard
• DIN standards
• ISO/IEC standards

All of these systems provide a reliable basis for eval­u­at­ing the planning, im­ple­men­ta­tion, and launch of new data centers, as well as for op­ti­miz­ing and de­vel­op­ing the per­for­mance and security existing data centers.

Uptime Institute’s Tier Clas­si­fi­ca­tion System is one of the most prominent standards and clas­si­fies data centers using a hi­er­ar­chi­cal system. The four tiers indicate where a data center stands regarding uptime, security, and re­dun­dan­cy.

The levels touch on external factors like con­nec­tiv­i­ty and the hierarchy of data centers in in­ter­na­tion­al networks, as well as internal factors like security measures and data center downtime.

The system is pro­gres­sive, meaning that each higher tier also includes the re­quire­ments of the tiers below it. Below we’ll look in detail at the re­quire­ments for each data center tier.

• No re­dun­dan­cy
• Single path for power and cooling
• No fault tolerance, not con­cur­rent­ly main­tain­able
• Limited cooling capacity: 220-230 watts per square meter
• Expected 99.67% uptime (maximum 28.8 hours of downtime per year)
• Suited for: Small companies and startups with low budgets and limited IT re­quire­ments. Not used very often

• Partial re­dun­dan­cy for cooling and power
• One path for power
• Low fault tolerance, not con­cur­rent­ly main­tain­able
• Simple cooling capacity: 430-540 watts per square meter
• Expected 99.75% uptime (maximum 22 hours of downtime per year)
• Suited for: Simple IT processes that require good per­for­mance but aren’t mission critical. Not used very often.

• Reliable re­dun­dan­cy for different com­po­nents: two servers, multiple paths for cooling and power
• Good fault tolerance, con­cur­rent­ly main­tain­able
• Good cooling capacity: 1,070-1,620 watts per square meter
• Expected 99.98% uptime (maximum 1.6 hours of downtime per year)
• Suited for: Rec­om­mend­ed minimum level for busi­ness­es with high standards for seamless IT processes, e-commerce, and mission-critical processes

• Complete re­dun­dan­cy for all parts of the system, including power and cooling
• Very high fault tolerance, no single points of failure
• Very good cooling capacity: over 1,620 watts per square meter
• Expected 99.991% uptime (maximum .8 hours of downtime per year)
• Suited for: Large companies with in­ter­na­tion­al­ly connected computing networks, 24/7 system avail­abil­i­ty, and highly mission-critical IT processes

The TIA-942 standard is another data center clas­si­fi­ca­tion system that’s fre­quent­ly used in the US. Released in 2005, it was among the first standards specif­i­cal­ly geared towards data centers. It covers site selection and layout of the space, cabling in­fra­struc­ture, and en­vi­ron­men­tal con­sid­er­a­tions and includes a tiered re­li­a­bil­i­ty system based on Uptime’s. The standard is par­tic­u­lar­ly relevant to the design and im­ple­men­ta­tion of new data centers.

In addition to the two American-based data center standards we’ve discussed, there are also in­ter­na­tion­al standards like DIN EN 50600 and ISO/IEC 22237. The DIN EN 50600 is a European standard that primarily focusses on physical security in data centers. The ISO/IEC 22237 was recently in­tro­duced by the In­ter­na­tion­al Or­ga­ni­za­tion for Stan­dard­iza­tion (ISO) and In­ter­na­tion­al Elec­trotech­ni­cal Com­mis­sion (IEC) and borrows heavily from the DIN EN 50600. It’s valid in­ter­na­tion­al­ly and is expected to replace Uptime’s tier clas­si­fi­ca­tion for data centers as well as DIN EN 50600.

The ISO/IEC 22237 adopts the most important points from the DIN EN 50600 and expands on them using recent findings on sus­tain­abil­i­ty and energy ef­fi­cien­cy. It also in­te­grates a four-tiered system for clas­si­fy­ing quality and uptime. It’s thus not only a valuable tool for de­vel­op­ers and planners but also a way to build trust with investors and end users. The standard consists of seven main points:

• ISO/IEC 22237-1 (EN 50600-1): General concepts
• ISO/IEC TS 22237-2 (EN 50600-1): Building con­struc­tion
• ISO/IEC 22237-3 (EN 50600-2): Power dis­tri­b­u­tion
• ISO/IEC 22237-4 (EN 50600-3): En­vi­ron­men­tal control
• ISO/IEC TS 22237-5 (EN 50600-4): Telecom­mu­ni­ca­tions cabling in­fra­struc­ture
• ISO/IEC TS 22237-6 (EN 50600-5): Security systems
• ISO/IEC TS 22237-7 (EN 50600-3-1): Man­age­ment and op­er­a­tional in­for­ma­tion

Standards, tiers, and cer­ti­fi­ca­tions are not mandatory ⁠— data centers par­tic­i­pate vol­un­tar­i­ly in them. There are also in­de­pen­dent or­ga­ni­za­tions that review data centers’ com­pli­ance with standards. This makes it even more important for investors, consumers, and end users to look out for a trans­par­ent in­di­ca­tion of which tier a data center belongs to. It’s also in the interest of those running data centers to increase their cred­i­bil­i­ty with standards and cer­ti­fi­ca­tions.