There has been a lot written about how much power is consumed by the computers that drive the Internet. A lot has been written about “green” data centers. But I think there’s a far more significant trend when, combined with more efficient computers and data centers, will make a 10x or greater reduction in power demand possible: cloud computing.
Data centers, brown or green are huge buildings — they are truly incredible places, with thousands of computers owned by multiple companies. I have negotiated the contracts for “co-location” in a number of data centers: you pay for floor space, bandwidth, and power and get a facility that has great connectivity, power that never goes out, and a carefully cooled environment for the computers. This blog, and most other websites are located at such data centers. Little sites like this one share a “slice” of a server with a number of others. Large sites like the ones we have at the Internet companies I have worked at have our own computers and other equipment “co-located” in data-centers.
I have been paying attention to power since 1998 when we moved the first servers for the Direct Hit search engine to a co-lo. Our first boxes were about 8″ tall, and bolted to special racks, and I think we got 7 to a rack, along with a few other needed parts. These days computers are many times more powerful, yet are 1/4 as tall — “pizza boxes” — thin computers that use a lot of juice, and put out that much more heat.
One of my companies had a space with ~100 servers at a facility in Waltham, MA but had to move — the data center “ran out” of power (the city/utility could not get variances for new power lines to their location). Over time the demand for space has decreased as servers get smaller, but the need for electrical power increased both because the servers needed more, but also the cooling systems (and backup generators) all needed to get larger.
One way to think of a data center is a bunch of hair dryers running continuously in a room whose temperature must be kept lower than 65° with air conditioning. Not a pretty picture.
Green Data Centers, Green Servers
Recently, data centers started figuring out that using good air-control methods, they could cool only the area in which servers were located, and (duh!) in cooler locales could draw in cold air from outside rather than using air-conditioners to make it. Facilities in hot locations are finding that the payback rates on improved insulation to keep the heat out are very quick. A few other tricks reduce the amount of energy needed both to power the computers, then cool the air they heat up.
And yes, data centers are also mounting solar panels on their roofs and coming up with other ways to reduce their consumption of power off the grid. But they aren’t doing this because it makes them look good — they are using solar and wind power, because big buildings with big roofs are perfect for this. It’s cost-effective.
These are “green” data centers.
Another factor, of course is the computers themselves. Servers are real power hogs — the ones we use in our current data center are between two and five years old use between 150W and 250W. Computers available today have more processing power, but draw a lot less power — here’s one from Silicon Mechanics that reports using only 122 Watts. This is good progress; more processing power (and therefore fewer computers) for less power.
These are “green” computers.
But green data centers and more efficient computers are only a small part of what will drive the biggest efficiency gains in the next few years. Here’s why.
The Incredible Expense of Redundancy
My company runs a number of eCommerce web sites. We do not make any money if the site is not working. So it always works (I just crossed my fingers and knocked on wood) — but the complexity and cost associated with this requirement is large indeed.Presently, my company, DigitalAdvisor has a number of servers located at a data center in Boston for some of our large sites. We have enough servers to handle double our “peak load” — the number of requests we get at the highest volume time. (A website can have the good fortune of getting a link in some widely read publication — volume can increase by two or three time in a matter of minutes. And of course you plan for bad things to happen.) For our high-availability database servers, we have “hot spare” servers that we can switch to if the main one fails. We have two of everything, and its all plugged in, and most of it is sucking power … all the time. In one cabinet, we have a dozen servers running full time, drawing around 2500W. Oh, plus several more we run out of our office server room (which has a special air-conditioner we use in the summer).
But all of these computers are tremendously under-utilized most of the time. We run at between 1/8 to 1/4 of our available capacity for about 80% of the time during a normal day. Total running expense (not including the expense of the hardware itself) for one cabinet is around $2500/month, of which most is electricity: about 1/2 for running the servers, and the other half for cooling them. That’s a lot of electricity wasted — efficient processors or not.
The Efficient, Elastic Computing Cloud
However, based on my experience, the single most significant “green” change to hosted computing will be a result of cloud computing.
We’re now completing our move to Amazon Elastic Computing Cloud (EC2). Yep, this is the same Amazon that you buy stuff from, but they have this other, rather incredible business. It has been in the works for years, but just in the last few months has gotten the features and service levels to be appropriate for sites demanding extremely high availability like ours. Why are we moving? Not because it was a green choice, but because it cost so much less.
We get our own server “machine instances” — they work just like the servers we have at our Boston facility but they are “virtual” — we don’t have any hardware to buy or place to go to look at them. If we need a new machine instance for additional capacity, we start one (from a template that we have configured and saved) and the meter starts running — we pay by the hour.
Because we need to run only as many servers as we need at the moment, we waste very little. As demand increases we add server instances, and we take them offline as it falls. If a server fails, we just fire up a new instance of it (automatically in <2 minutes). If we need to test something, we run an instance for an hour or so, do our release and then away it goes. We don't need redundant power, redundant servers, spare capacity, complicated fail-over processes, servers used only for backup, development, staging, and periodic processing. And our equipment never gets outdated. We still have all the capacity we need and ability to recover from failures. Our running costs will be about 70%-80% lower, and we’ll have no server hardware investment. We’ll get a more reliable, flexible, managed, and even geographically dispersed installation. (In fairness, it’s a little more complicated to set up … although in some ways, its a lot easier).
Just because we can’t actually see our hardware, there is hardware behind all of this — computers, CPUs, and hard disks. And they do use electricity. However, even these servers are more efficient, because they use “virtualization” — our machine instance may be one of many on a single actual physical machine in one of Amazon’s data centers. Virtual servers perform just like a single actual machine, but the hardware (and operating systems) are designed to support many virtual servers at once. Through virtualization, Amazon uses up the full capacity of any one real server before they turn on (or buy) more. Servers use about the same amount of power when they are idling as when they are working … we make them work!
The Virtual Green Cloud is Here
So look at cloud computing from an overall energy standpoint — we use about 80% less server power, thus need that much less cooling and that many fewer computers. Add virtualization and we use even fewer physical resources so the “embedded energy” of the hardware is even less.
The only losers in this whole new paradigm: the data centers (at least the ones who haven’t gone to cloud computing on their own) and the computer manufacturers.
Solar panels on the roof, more efficient cooling, and other “green data center” features are great improvements. But by enabling us to stop wasting power and resources our business, which is just one of many thousands like it, will save money and be green in a cloud computing environment.