Data Center Tiers Explained

A Data Cave Presentation

Why do we

need Tiers?

Some background

Why do we have tiers? What do they indicate?

• With so many data centers of varying sizes, a standard was needed that could be used to consistently identify a data center’s overall capabilities and level of service.

• The 4-Tier ranking system was established in 2005 to be this unique standard for the data center industry.

The criteria for each of the 4 tiers primarily focuses on a data center’s:

• Infrastructure• Levels of redundancy• Promised uptime level

Breaking down

the 4 Tiers

The Tier I Data Center

Expected Uptime:99.671%

Single path for power and cooling to the server equipment, with no redundant components.

Typically lacks features seen in larger data centers, such as a backup cooling system or generator.

Very little (if any) levels of redundancy.

The Tier II Data Center

Expected Uptime:99.741%

Will typically have a single path for both power and cooling, but will utilize some redundant components.

These data centers have some backup elements, such as a backup cooling system and/or a backup generator.

Some redundancy measures are active.

The Tier III Data Center

Expected Uptime:99.982%

Multiple power and cooling distribution paths to servers, to ensure availability if one path fails.

Multiple power sources for all IT equipment.

Considerably higher availability and uptime.

Specific procedures that allow for maintenance to be done in the data center, without causing downtime.

The Tier IV Data Center

Expected Uptime:99.995%

Fully meets all requirements for Tiers I-III.

Fully fault tolerant infrastructure; it can function normally even in the event of 1 or more equipment failures.

A truly maximum level of uptime.

Redundancy in everything: Multiple cooling units, backup generators, power sources, chillers, etc.

What

RepresentsTier IV

What Tier IV Represents

A Tier IV ranking indicates that a data center canmaintain a truly maximum uptime level through its:

• Redundant components and supporting hardware• Facility’s physical construction and security• Fully fault tolerant infrastructure• Internal processes/procedures

With uptime levels of 99.995%, a Tier IV data center could experience up to 26 minutes of downtime annually.

Compare that to a Tier I data center: At 99.671% uptime, they can see up to 1,729 minutes of downtime annually!

Fun fact:

Data Center Tiers Explained

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