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Things you need to operate a successful Data Center infrastructure.

This is a first in a series of Toolbox topics others include
"Watts per Sq.Ft.of What"
"Use of a Hand Held IR (Infra Red) Gun for a Data Center Health Check"
"Generic Data Center Racking, Cost and Space Benifits"
"Data Center Layer One and Structured Cabling Designs, Without Costly Patch Panel Installations"

As a data center operations manager you are reasonable for the stability of the physical infrastructure of your environment. Often this requires support from maintenance and or engineering staff to provide you with capacity and room loading calculations. In order for you to do your job efficiently and not be reliant on others you need a few tools to Help You Help Yourself the first in a series is:

*Data Center Math
*Power and Thermal Measurement

Watts (w) = Volts (V) x Amps (A)

Voltage x Amps = KW (Kilo Watts) (This is Electrical Heat)
1000 w

British Thermal Unit (BTU) (measure of heat)

One Watt of Power requires 3.432 BTU's to cool

12,000 BTU's = One Ton of Cooling

Example;
120 Volts x 160 Amps = 19,200 Watts = 19.2 kW

19,200w x 3.432 BTU = 65,894 BTU = 5.5 Tons of Cooling Required
One Ton of Cooling = 12,000 BTU

Power Basics:
Reduce all loads to Watts as the common measurement including cooling. If you use Watts as the common unit you do not need Amps or Voltage when determining capacities.


Power Rough Rules of Thumb
• One average rack of 2u to 8u servers, (40u's total) use~ 5000watts
• One disc type storage bay(24inches)is ~5000watts
• One network equipment rack ~ 30 to 40u's of switches requires 5000w to 6000w
• The average server landing power requirement with redundant network and redundant disc storage is 400watts per server
• The average server landing power requirement with single network switch and single storage connectivity is 300watts per server
• The average "One U" server rack with 40 servers per rack ranges between 7500w to 9000w depending on utilization
• One blade center is 3600w to 4000w

Cooling Rough Rule of Thumb
One blade center @3600watts requires 1 ton of cooling.
• One rack of 2u through 8u servers, (40u's total) required 1 1/2 (one and one half) tons of cooling
• The industry standard rack doors can restrict up to 40% of the air flow
• If using "relative humidity set points" set @ 50% plus or minus 20% this will reduce alarms and operating cost
• Available supply air temperature at the server intake can be as high as 80 degrees Fahrenheit without issues

If this Information is useful please comment

*Disclaimer
The opinions, suggestions, management practices, room capacities, equipment placement, infrastructure capacity, power and cooling ratios are strictly the opinion and observations of the author and presenter.
The statements, conclusions, opinions, and practices shown or discussed do not in any way represent the endorsement or approval for use by Intel Corporation.
Use of any design practices or equipment discussed or identified in this presentation is at the risk of the user and should be reviewed by your own engineering staff or consultants prior to use.

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Add a comment Leave a comment on this blog post.
Sep 28, 2007 8:18 AM Reply Guest Brad

Very informative. Thanks

Sep 28, 2007 4:40 PM Reply Guest Israel

Nice post, wished i found this information last time I had to build out a DC.

Nov 3, 2007 2:45 PM Reply Guest Yigal

John,
Thank you for this informative post. My experience, however, is that using standard rules of thumb is what gets people in trouble when they use high density computing such as 4-5 blade centers in a rack. Adding 10 tons to the room when adding 10 bladeCenters in 2 cabinets will not be effective. So I would add a cautious note that these rules may not apply for high density. What do you think?

Nov 7, 2007 3:47 PM Reply Guest John Musilli in response to: Yigal

Thank you for pointing this out. You are absolutely correct. When you land that concentration of heat in your example 14kw to 18kw (3600w per blade center) you have to have a significant amount of cold air requirements 1400 to 1700 CFM (Cubic Feet per Minuet) delivered to the racks. Even if you had high flow grates in the rack cooling zone you will most likely starve adjacent areas causing isolated “Hot Spots”

To all readers Blades and full racks of 1u servers can be handled successfully even in a data center designed at 50w/sf but you will have to use the Rule of Thumb and your head to properly distribute the heat loads.
JM

Nov 12, 2007 10:11 AM Reply Click to view mryan13's profile mryan13

Good discussions to real problems. Thanks........

Jan 29, 2008 7:03 AM Reply Guest Listener

Very useful article, thank you
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