Data center tiers

There are a number of na­tion­ally and in­ter­na­tion­ally re­cog­nised standards for ensuring the quality, avail­ab­il­ity, and security of data centres. 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 centre tier clas­si­fic­a­tion systems provide in­form­a­tion about the centres’ 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 strong data centres, cloud computing, and software-defined data centres. The more connected our social and pro­fes­sion­al worlds become, the more important it is to ensure security in data centres, 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 centre’s suit­ab­il­ity for your business.

There are four systems commonly used to evaluate data centres:

• 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 centres, as well as for op­tim­ising and de­vel­op­ing the per­form­ance and security existing data centres.

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

The levels touch on external factors like con­nectiv­ity and the hierarchy of data centres in in­ter­na­tion­al networks, as well as internal factors like security measures and data centre 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 centre 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 start-ups 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 centre clas­si­fic­a­tion system that’s fre­quently used in the US. However, it can be a useful guide for companies in­ter­na­tion­ally. Released in 2005, it was among the first standards spe­cific­ally geared towards data centres. 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 centres.

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 centres. 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 centres 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 centres par­ti­cip­ate vol­un­tar­ily in them. There are also in­de­pend­ent or­gan­isa­tions that review data centres’ 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 centre belongs to. It’s also in the interest of those running data centres to increase their cred­ib­il­ity with standards and cer­ti­fic­a­tions.