17 Tier Standard Prt2

8/13/2019 17 Tier Standard Prt2

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Data Center Site Infrastructure

Tier Standard: Topology

Dr. Natheer Khasawneh

Sadeem Al-Saeedi (8276)


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This Section will cover the Following

Commentary for Application of the Tier StandardTopology

Outcome-Based Tier Standard

Impact of Ambient Design Conditions

Tier Functionality Progression Fractional or Incremental Tier Classification


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Outcome-Based Tier Standard

The definitions used are necessary and intentionallyvery broad to allow innovation and client

manufacture in achieving the desired level of site

infrastructure performance or uptime.

The operational outcomes that define the four Tiers

are very straightforward. Many designs that pass a

checklist approach will fail an operational

performance requirements approach.


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Tier I

Tier I sites experience 2 separate 12-hour, site-wideshutdowns per year for maintenance or repair work.

In addition, Tier I sites experience 1.2 equipment or

distribution failures on average each year.

The annual impact of maintenance and unplanned

outages is 28.8 hours per year, or 99.67 percent

availability.


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Tier II

Tier II sites (On Average) schedule 3 maintenanceover a 2-year period and have 1 unplanned outage

each year. The redundant components of Tier II

topology provide some maintenance opportunity

leading to just 1 site-wide shutdown each year.

The annual impact of maintenance and unplanned

outages is 22 hours per year, or 99.75 percent

availability.


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Tier III

Tier III topology is Concurrently Maintainable, soannual maintenance shutdowns are not required, but

needs aggressive maintenance program improving

overall equipment performance.

Unplanned failures are up to 4-hours event every 2.5

years, or 1.6 hours on an annual basis. Tier III sites

demonstrate 99.98 percent availability


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Tier IV

Tier IV provides robust, Fault Tolerant siteinfrastructure

Unplanned failures are up to 4-hours event in a5-year operating period, or 0.8 hours on an

annual basis. Tier IV sites consistently demonstrate 99.99

percent availability.

Availability calculations do not determine the Tier

Classification.e.g. A site with a measured infrastructureavailability of 99.90 percent


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Impact of Ambient Design Conditions

Cont..

Another concern arises when selecting heat rejectionsystems. Many manufactures provide product based

on 95F (35 C) ambient outside conditions. These

components will be at best when operating in up to

95F (35 C) outside air.

These component capacities must be adjusted

downward to provide the required capacity when

temperatures exceed 95F.


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Tier Functionality Progression

Tier I and Tier II solutions are typically solutions toshort-term requirements, they are usually tactical

solutions, driven by first-cost and time-to-market

more than life-cycle cost and uptime (or availability)

requirements. Long-term viability found more often in Tier III and

Tier IV site infrastructure.

Strategic site infrastructure solutions enable the

owner to make strategic business decisionsconcerning growth and technology, unconstrained by

current site infrastructure topology.


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Tier I FP

Tier I solutions acknowledge the owners desire fordedicated site infrastructure to support IT systems.

Tier I infrastructure provides an improved

environment over an ordinary office setting andincludes: a dedicated space for IT systems; a UPS to

filter power spikes, sags, and momentary outages;

dedicated cooling equipment not shut down at the

end of normal office hours; and an engine generatorto protect IT functions from extended power outages.


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Tier II FP

Tier II solutions include redundant critical power andcooling capacity components to increase the margin

of safety incase of infrastructure equipment failures.

The redundant components are typically extra UPSmodules, chillers, heat rejection equipment, pumps,

cooling units, and engine generators. A malfunction

or normal maintenance will result in loss of a

capacity component.


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Tier III FP

Tier III site infrastructure has ConcurrentMaintenance.

Concurrent Maintenance means that each and every

capacity or distribution component can bemaintained on a planned basis without impact to the

IT environment.

Maintenance allows the equipment and distributionpaths to be returned to like new condition on a

frequent and regular basis, Thus, the system will

reliably and predictably perform as originally

intended.


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Tier III FP Cont

Moreover, each and every system or component thatsupports IT operations must be able to be taken

offline for scheduled maintenance without impact to

the IT environment.

This concept extends to important subsystems such

as control systems for the mechanical plant, start

systems for engine generators, EPO (Emergency

Power Off System) controls, power sources forcooling equipment and pumps, isolation valves, and

others.


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Tier IV

Tier IV site infrastructure builds on Tier III, adding theconcept of Fault Tolerance to the site infrastructure

topology.

Fault Tolerance extends to each and every system orcomponent that supports IT operations. Tier IV

considers that any one of these systems or

components may fail or experience an unscheduled

outage at any time.


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Tier IV Cont

However, the site must be designed and operated totolerate the cumulative impact of every site

infrastructure component, system, and distribution

path disrupted by the failure. E.g. the failure of a

single switchboard will affect every subpanel andequipment component deriving power from the

switchboard. A Tier IV facility will tolerate these

cumulative impacts without affecting the operation of

the computer room.


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Fractional or Incremental Tier

Classification

The four Tier Classifications address topology, orconfiguration of a site rather than a list of

components to achieve a desired operational

outcome.

For example, the same number of chillers and UPS

modules can be arranged on single power and

cooling distribution paths resulting in a Tier II solution

(Redundant Components), or on two distributionpaths that may result in a Tier III solution

(Concurrently Maintainable).


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Fractional or Incremental Tier

Classification Cont

Selecting the appropriate topology solution based onthe IT availability requirements, and the substantialfinancial consequences for downtime, provides thebest foundation for investment in data centerfacilities.

Fractional or incremental descriptions for siteinfrastructure are not appropriate and aremisleading. (Tier III +, Enhanced Tier III, or Tier IV-

lite)

Including a criteria or an attribute of a higher TierClassification in the design does not increase the

overall Tier Classification

F t I t T


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Fract ona or Incrementa T erClassification Cont 1) A site that has an extra (redundant) UPS module

but needs all the installed cooling units running tokeep the computer room temperature within limitsdoes not meet the redundancy requirements for TierII.

2) A switchboard that cannot be shut down withoutaffecting more than the redundant number ofsecondary chilled water pumps (reducing theavailable capacity to less than N) is not Concurrently

Maintainable and will not be Certified as Tier III.

3) Including a UPS system patterned after a Tier IVsystem within a site having a Tier II powerdistribution backbone yields a Tier II Certification.


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Non-Compliance Trends The most significant deviations from the Tier

Standard found in most sites can be summarized asinconsistent solutions.

A site will have a robust, Fault Tolerant electrical

system patterned after a Tier IV solution, but utilize aTier II mechanical system that cannot be maintainedwithout interrupting computer room operations. Thisresults in an overall Tier II site rating.

The mechanical system fails ConcurrentMaintenance because of inadequate coordinationbetween the number and location of isolation valvesin the chilled water distribution path.


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Non-Compliance Trends Cont..

If more than the redundant number of chillers, towers, or

pumps are de-energized for electrical maintenance,computer-room cooling is impacted.

Electrical systems often fail to achieve Tier III or Tier IVcriteria due to design choices made in the UPS and the

critical power distribution path.

Topologies that include static transfer switches in thecritical power path for single-corded IT devices will likelyfail both the Fault Tolerance criteria and the ConcurrentMaintenance criteria.

Consistent application of standards is necessary to havean integrated solution for a specific data center.


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Non-Compliance Trends Cont..

An investment in one segment must be met with a similar

investment in each of the other segments if any of the elements in

the combined solution are to have the desired effect on IT

availability. A well-executed data center master plan or strategy

should consistently resolve the entire spectrum of IT and facility

requirements.

17 Tier Standard Prt2

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