Data Center Design IssuesBill Tschudi, [email protected]
Design IssuesDesign Issues
IT equipment loadIT equipment load RedundancyRedundancy Data center airflowData center airflow Environmental conditionsEnvironmental conditions ZoningZoning Isolating hot and coldIsolating hot and cold
IT Equipment LoadIT Equipment Load
Predicting IT loadsPredicting IT loads– Over sizing, at least initially, is commonOver sizing, at least initially, is common– Implement modular and scalable approachesImplement modular and scalable approaches
IT loads can be controlledIT loads can be controlled– Power supply optionsPower supply options– Server efficiencyServer efficiency– Software efficiency (Virtualization, MAID, etc.)Software efficiency (Virtualization, MAID, etc.)– Redundancy and back-up powerRedundancy and back-up power– Low power modesLow power modes
Reducing IT load has a multiplier effect Reducing IT load has a multiplier effect
ASHRAE Prediction of Intensity ASHRAE Prediction of Intensity TrendTrend
RedundancyRedundancy
Understand what redundancy Understand what redundancy costs – is it worth it?costs – is it worth it?
Different strategies have Different strategies have different energy penalties (e.g. different energy penalties (e.g. 2N vs. N+1)2N vs. N+1)
Redundancy in electrical Redundancy in electrical distribution always puts you down distribution always puts you down the efficiency curvethe efficiency curve
Measured UPS Efficiency
Redundant Operation
Air Flow RequirementsAir Flow Requirements
Typically, much more air is circulated Typically, much more air is circulated through computer room air conditioners through computer room air conditioners than is specified by manufacturers due than is specified by manufacturers due to mixing and short circuiting of airto mixing and short circuiting of air
Computer manufacturers now provide Computer manufacturers now provide ASHRAE data sheets which specify ASHRAE data sheets which specify airflow and environmental requirementsairflow and environmental requirements
Evaluate airflow from computer room air Evaluate airflow from computer room air conditioners compared to server needsconditioners compared to server needs
Visualizing Air FlowVisualizing Air Flow
Computational Fluid Computational Fluid Dynamics (CFD) modeling Dynamics (CFD) modeling
Temperature sensor Temperature sensor networksnetworks
Infrared thermographyInfrared thermography
Environmental ConditionsEnvironmental Conditions
ASHRAE - consensus ASHRAE - consensus from all major IT from all major IT manufacturers on manufacturers on temperature and temperature and humidity conditionshumidity conditions
Recommended and Recommended and Allowable ranges of Allowable ranges of temp and humiditytemp and humidity
Air flow requiredAir flow required
Other ASHRAE ResourcesOther ASHRAE Resources
Four books Four books published—more published—more in preparationin preparation
Temperature Guidelines – Temperature Guidelines – at The Inlet to IT Equipmentat The Inlet to IT Equipment
ASHRAE TEMPERATURE GUIDELINES
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Degrees F
ASHRAE Allowable Maximum
ASHRAE Allowable Minimum
ASHRAE Recommended Maximum
ASHRAE Recommended Minimum
Humidity Guidelines— Humidity Guidelines— at The Inlet to IT Equipmentat The Inlet to IT Equipment
ASHRAE HUMIDITY GUIDELINES
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% Relative Humidity
ASHRAE Allowable Maximum
ASHRAE Allowable Minimum
ASHRAE Recommended Maximum
ASHRAE Recommended Minimum
ZoningZoning
Some IT equipment (e.g. storage) Some IT equipment (e.g. storage) requires tighter controlrequires tighter control
Don’t penalize the whole center Don’t penalize the whole center for a few pieces of equipmentfor a few pieces of equipment
Different zones should be Different zones should be providedprovided
Isolating Hot and ColdIsolating Hot and Cold
Energy intensive IT equipment needs Energy intensive IT equipment needs good isolation of “cold” inlet and “hot” good isolation of “cold” inlet and “hot” dischargedischarge
Computer room air conditioner airflow Computer room air conditioner airflow can be reduced if no mixing occurscan be reduced if no mixing occurs
Overall temperature can be raised in Overall temperature can be raised in the data center if air is delivered to the data center if air is delivered to equipment without mixingequipment without mixing
Coils and chillers are more efficient Coils and chillers are more efficient with higher temperature differenceswith higher temperature differences
Best Scenario— Best Scenario— Isolate Cold and HotIsolate Cold and Hot
70-75ºF
95-100ºF
Another Isolation SchemeAnother Isolation Scheme
Fan Energy SavingsFan Energy Savings – 75%– 75%
If mixing of cold supply If mixing of cold supply air with hot return air air with hot return air can be eliminated-can be eliminated-fan speed can be fan speed can be reducedreduced
Better Temperature Control Better Temperature Control Can Allow Raising the Can Allow Raising the Temperature in The Entire Data Temperature in The Entire Data CenterCenter
Cold Aisle NW - PGE12813
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6/13/2006 12:00 6/14/2006 0:00 6/14/2006 12:00 6/15/2006 0:00 6/15/2006 12:00 6/16/2006 0:00 6/16/2006 12:00
Time
Temperature (deg F)
Low
Med
High
Baseline Alternate 1
Setup
Setup
Alternate 2
ASHRAE Recommended Range
Ranges during demonstration
Take AwaysTake Aways
IT equipment loads can be improvedIT equipment loads can be improved Air flow delivered by computer room air Air flow delivered by computer room air
conditioners must satisfy IT equipment conditioners must satisfy IT equipment Different redundancy strategies have Different redundancy strategies have
different efficienciesdifferent efficiencies Operating within ASHRAE guidelines can save Operating within ASHRAE guidelines can save
energy energy Modern IT equipment is not sensitive to Modern IT equipment is not sensitive to
humidityhumidity Isolating hot and cold can improve efficiencyIsolating hot and cold can improve efficiency
website: website: http://hightech.lbl.gov/datacenters/http://hightech.lbl.gov/datacenters/