Datacenter Tiers Tier1-Tier2-Tier3-Tier4 – POFTUT

Datacenter Tiers Tier1-Tier2-Tier3-Tier4

A data center is a facility used to house computer systems and provides required environment to these systems. Old days data center was a bit luxury but today’s situations a lot of SMB’ have data centers.

Problems Of Data Centers

We expect a Windows server to run forever but its not. A electricity outage may bring down the system if the data center have not enough UPS power. A bug in the network infrastructure will bring down the network. We can say a lot of different scenarios which may effect the health and expected operation of data center.


We can not prevent the unexpected events but lower their operations effects by making plans and redundancy. Also we can meter the outage level and duration by setting limits.. But Telecommunication Industry Association (TIA) all ready did this with start ANSI/TIA-942 . In this standard there are four levels to meter the outage. The level are called Tiers like Tier-1, Tier-2, Tier-3, Tier-4 . We will look in detail below to these Tiers.


The lowest level of the ANSI/TIA-942 standard. Single non-redundant distribution path serving to the IT equipment is required in this level. Also non-redundant capacity components are used. Basic site infrastructure expected availability is 99.671% which will allow 1729 minutes or 28.8 hours outage


Meets or exceeds all Tier-1 requirements. Also redundant site infrastructure availability is 99.741% which is 1361 minutes or 22.6 hours outage.


Meets and exceed all Tiers-2 requirements. Also as a plus multiple independent distribution paths is required. All IT equipment must be dual powered. Up time percentage is 99.982% which means maximum 94 minutes. 1.5 hours outage.


Meets or exceeds all Tier-3 requirements. All cooling equipment is independently dual powered. Up time percentage is 99.995% which is equal to 26 minutes or 0.4 hours outage.

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