The Uptime Institute has standardized the tiered approach to classifying site infrastructure.
The Tier Classification system provides a standard in an industry where competing companies with data centers of radically different infrastructure.
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Tier Requirement
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Tier I
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Tier II
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Tier III
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Tier IV
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Source
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N
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N+1
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N+1
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Minimum N+1
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System Component Redundancy
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1
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1
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1 normal and
1 alternate |
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2 simultaneously active
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Distribution Paths
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No
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No
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Yes
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Yes
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Compartmentalization
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No
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No
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Yes
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Yes
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Concurrently Maintainable
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No
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No
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Yes
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Yes
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Fault Tolerance (single event)
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No
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No
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No
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Yes
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