Know thy data center Tier

A day does not go by when we can't learn something new. Love the "What I learned today" posts that Mike Laverick has been doing.

So here is what I learnt today, the right order for DC tiers.

Tier 1 is the lowest and tier 4 is the highest. The tiers are allocated to the different portions of the infrastructure such as:

• architectural
• security
• mechanical
• electrical
• communications

The overall rating of the data center is equal to the lowest tier rating.

Some details to show the differences¹.

Tier 1 - Basic data center with no redundancy

• No redundancy
• Susceptible to disruptions from both planned and unplanned activity
• May or may not have raised floor, UPS or generator
• Shut down likely to perform preventive maintenance
• Annual downtime of 28.8 hours

Tier 2 - Redundant components

• Single distribution path with redundant components
• Less susceptible to disruption from both planned and unplanned activity
• Single path for power and cooling disruption, includes redundant components (N+1)
• Includes raised floor, UPS and generator
• Annual downtime of 22 hours

Tier 3 - Multiple distribution paths with only one active

• Enable planned activity without disrupting computer hardware operation, but unplanned events will still cause disruption
• Multiple power and cooling distribution paths but with only one path active, includes redundant components (N+1)
• Includes raised floor and sufficient capacity and distribution to carry load on one path while performing maintenance on the other
• Annual downtime of 1.6 hours

Tier 4 - Multiple active distribution paths

• Planned activity does not disrupt critical load and data center can sustain at least one worst-case unplanned event with no critical load impact
• Multiple active power and cooling distribution paths, includes redundant components (2(N+1)), such as 2 UPS each with N+1 redundancy
• Annual downtime of 0.4 hours

If you are after some more details check out ANSI/TIA-942.

Today I got a peek at a T4 center and some space that housed the legal black hats / spies. Some nice high end stuff. I bet it was just a decoy. They probably have the things everywhere! You would not want to stick the Cloud next door to that, I bet they have cameras facing outwards and can read data streams by watching the flashing lights on the disks. Well if they can't I bet someone wrote a PhD thinking about how you might.

Rodos

¹ TIA-942:Data Center Standards Overview Uptime Institute Paper on Tiers