One word that you often see associated with any data center is its “tier,” or its level of service. Virtually every data center has a tier ranking of I, II, III, or IV, and this ranking serves as a symbol for everything it has to offer: its physical infrastructure, its cooling, power infrastructure, redundancy levels, and promised uptime. This presentation takes a look at each of the 4 data center tiers, examining the key components for each tier, as well the total expected uptime level for each tier. If you are in the process of evaluating data centers, this is no doubt a term you will come across in your search, so we hope this presentation helps provide some solid background in to how you can better choose a data center for your specific needs. For more insights into the data center world, and to learn more about Data Cave, check out our website at www.thedatacave.com.

1. Data Center Tiers Explained
A Data Cave Presentation

2. Why do we
need Tiers?

3. 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

4. Breaking down
the 4 Tiers

5. 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.

6. 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.

7. 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.

8. 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.

9. What
Represents
Tier IV

10. What Tier IV Represents
A Tier IV ranking indicates that a data center can
maintain 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

11. 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:

12. Data Center Tiers Explained
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