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Building an Energy Efficient Datacenter?
asc4 asks: "The company I work for is a webhosting and colocation company. As our power utilization grows, we have begun searching for ways to make our datacenter more efficient. The biggest hit from the utility company comes in the peak usage charge, which penalizes (rather severely) for the highest sustained burst of usage during a billing period. Due to the nature of the colocation business, we can't control how much or when client devices use power, so I'm wondering: is there's something we can do at the datacenter level to help smooth out our power consumption, over the course of a given period of time?"
"In these days of hybrid cars, Energy Star devices, and in general more eco-friendly power consumption, it seems like there must be some products out there that can help make datacenters more efficient, as well. Could fuel cell technology be something to look into? Would flywheels or capacitors help? How about using more efficient AC units than what are available from the big names? What are others doing to reduce peak power consumption in high-drain datacenter environments?"
Once you get a feel for how the datacenter is 'breathing' (i.e. watch the usage graphs and become familiar with the pulse of workload, etc) you should be able to come up with good solutions to your problems (like starting your monthly billing processes 2 days early, so you can only run the batch processes at night when the power is cheaper).
Also, never underestimate the cost of lighting and A/C. Maybe you can get by with only turning on every 3rd fluorescent light. Maybe you can use exhaust fans instead of A/C in a colder climate.
The point is you'll never know what problems you need to address unless you monitor your DC.
For smoothing out power usage, there are a number of different options -- aside from alternative energy, you could do rolling brownouts throughout your datacenter and rely on UPSes or generators to keep things going -- but you *will* take a hit in reliability. Every switchover -- one mains circuit to another, mains to battery, etc. -- carries some risk.
I've watched an entire datacenter go out on what was supposed to be a controlled switchover -- power company needed to do some work, pulled the plug (with the datacenter's consent), the backup generators start... and then die. The UPSes kicked in, but could only supply 15-20 minutes of power. Everything failed over to a backup datacenter, whose link then decided to go out to lunch.
Total cost of the outage was measured in tens of millions of dollars.
Just keep this in mind when doing the business justification calculation (cost savings from lower energy bills, minus upfront cost of equipment, minus risk of additional downtime times cost of downtime, minus cost of maintaining the equipment). Unless energy prices go *way* up -- like oil hitting $250/barrel -- I'd be surprised if this would pay for itself.
1. Cool down the centre during the night when hydro is at its cheapest.
2. During the day raise the thermostat so the AC does not kick in too soon.
3. If you have windows use the blinds on the sunny side. Thermal load is a royal pain. Where I work it hit 27c inside even though it was -14c outside. The north side was running at about 21c.
4. Put all non-essential equipment on powerbars and turn off the bars. Most monitors and other electronics still draw a bit of current for 'instant on'. That takes hydro and dumps more heat for the AC to handle.
Panic now, beat the rush!
If you've got a datacenter large enough that energy efficiency is a problem, I recommend you move the whole shebang to a location where energy is more plentiful. Upstate NY, which has plenty of hydroelectric power, would be a good choice. Nowadays, thanks to the internet, you don't have to keep your datacenter next to part of your operation.