Need info about 'Tiers'

[BillP]

Dear Folks,

As we know about Tiers levels of data center. But anybody has an excellent, presentation, excel sheet, or any type of info with good examples and pictures about Tiers?????

e.g. If we talk about a Tier3 data center, how 'additional or extra' UPS's or Cooling Unit we would give?

Thanks in advance.

[BillP]

Dear adavid,

Yes I m totally agreed with u. The same thing I was thinking that the second power distribution module has represented as a vertical line. But yes it is not much clear. Any ways, Angela has shared with us a very good document plus I read a very good explanation for Tiers which is being shared with you.

"We now know that "Tier" ratings come in two versions: TIA-942-2 (TIA-942) and Uptime Institute Tier Standard: Topology (TS:T).

But are they really different?And if so, what are the core differences.


Well, they are different, and in some subtle but very important ways.

First, Both examine the resiliency of Power and Cooling systems.  However, TIA-942 also includes the categories of Architectural and Telecommunications. (That should be no surprise, as they are a Telecommunications Standards body).  In Truth, TS:T also includes telecommunications (cabling) to a limited degree, where multiple redundant routes are concerned (at Tier III) and routing compartmentalization (at Tier IV).  But that is the extent to which TS:T consider telecommunications.

The real core difference between the two, at the theoretical level, is what is considered the Primary source of Power to the site.  TIA-942 treats Utility Power Supply as the primary source for power.  At Tier 3 it requires N+1 Utility feed (so, a minimum of 2), and at Tier 4, 2N (Also, minimum of 2, but could require more, if 1 feed each will not suffice to provide total power to the site).  Generator power is used as a "bridge" only in the event that all Utility power is lost, with the expectation that utility power will be restored in a time shorter than there is fuel supply available to the generators.

TS:T treats on-site power generation as primary power, with utility power used as a low-cost alternative when available.  For Tier II and above, that requires redundancy in the generator set, but all are able to utilize N+1 generator set for redundancy, so long as the proper rules for down-stream power distribution are met which also provides for multiple power supply pathways under Tier III and Tier IV.  This carries some distinctions.  Under TS:T then, it is technically possible to achieve any Tier level with 0 incoming utility power feeds (So long as the site is able to provide continuous power generation, with redundancy for Tier II and above).  One key "gotcha" then when building a TS:T standard data center is to ensure that the generators are rated for either PRIME or CONTINUOUS run (as opposed to STANDBY rated).  If a PRIME generator is used, it must be de-rated by 70% of its capacity to meet the continuous run requirements (however, if agreed in writing with the manufacturer, it is possible to achieve up to 85% capacity for de-rating).  STANDBY generators are not robust enough for Tier III or Tier IV, but are suitable for Tier I and Tier II.  Generally, STANDBY generators are rated only to run 200 to 500 hours per year. (200 hours is 8 1/3 days, so by the time you reach day 9, you've hit maximum for the year.)


This distinction may seem trivial, however it is a crucial difference in the underpinning philosophy of TIA-942 compared to TS:T."

[BillP]

Dear Folks,

As we know about Tiers levels of data center. But anybody has an excellent, presentation, excel sheet, or any type of info with good examples and pictures about Tiers?????

e.g. If we talk about a Tier3 data center, how 'additional or extra' UPS's or Cooling Unit we would give?

Thanks in advance.

[Anonymous user]

i don't know of any pictures or presentations about data center tiers but Wikipedia has a decent table defining the differences, i don't believe i saw anything about tiers specifically in the APC white papers but they do have one on Data Center System Planning, and has a Data Center Design Planning Calculator that might give you the info you need.

it may not be exactly what you were looking for but i hope it helps some

[BillP]

Dear adavid,

I m truly appreciate your response. You have defined many things that are helpful. I just wanna share one thing..My attached file is not all an all, but clear some basic concepts.

[Anonymous user · Accepted solution]

the document you have is pretty good, i think the one for tier 3 is a bit off though but i could be wrong i'm not an expert.  i think you should have one ups on feed a and one on b, the description says it has redundant ups's but i do not see them in the image.  each rack should have a power feed from A and B giving the servers power redundancy.  i think that may be what that one vertical line is supposed to represent to the left of the power distribution modules but its not that clear. 

i don't believe you have redundant cooling in tier 3 but depending on the size of the room and the type of cooling units you choose you may have multiple units.  you would probably want multiple cooling units in a tier 3 set up so you could run maintenance on them without having to shut down the whole room or have it get incredibly hot.  you can sometimes compensate for one unit being down if you have other units that can step up their output.