Young says a third-party consultant who visited Joyent’s datacenter estimated the startup will save $1,200 per year for every T1-based server it uses, bringing the total saved from those machines to $30,000. The finding, which was part of an audit commissioned by Pacific Gas & Electric — the utility that serves Joyent’s new datacenter — came as something of an epiphany for Young. “The fact that all servers weren’t created equal when it comes to power consumption came onto our radar,” he says. Sweetening the deal was a rebate of almost $2,500 — or $989 per T1 box — that Joyent received from PG&E for the purchase.
The Sparc T1 servers were a logical choice for highly threaded applications such as Joyent’s database, identity, and e-mail servers. But they didn’t stack up as well on single-threaded applications, such as those based on Ruby on Rails. For the remainder of its revamped fleet, Joyent relied on Sun boxes built with AMD Opteron CPUs. Young estimates that the Opteron-based machines, which round out the remaining 80 percent of his revamped datacenter, deliver approximately 35 percent more throughput than his older servers while consuming the same wattage.
Still other options abound. While AMD and Sun started preaching the virtues of power efficiency before the topic was in vogue, Intel, after enduring unfavorable power comparisons between its Xeon and AMD’s Opteron for years, has come roaring back with its Woodcrest design, which roughly doubles the performance of the previous top-of-the-line Xeon while drawing 35 percent less power.
Meanwhile, HP and IBM have attempted to address power and space problems through their blade designs, but as mentioned, heat dissipation can become an issue with high-density racks. One solution is to reduce the total number of servers in deployment; even when servers are running efficient chips, analysts say too often the machines are underutilized.
“People for a long time have adopted a one-application-per-server model,” IDC’s Bailey says. What results are datacenters with hundreds of machines, each of which runs at a small fraction of its capacity. The problem is that a server that’s only 10 percent utilized draws almost as many watts as one that’s running at 80 percent capacity.
Bailey and other IT advisers say companies can reap big savings by consolidating a handful of small jobs onto a single box through virtualization technologies. On the extreme end of this trend, IBM also advocates the use of mainframes running virtualization software, which it says allows many of its customers to replace dozens of juice-thirsty servers with a single machine (albeit an expensive one).
Replacing old machines with more energy-efficient gear and consolidating servers are great initial steps, but real power savings in the datacenter can’t be accomplished until managers tackle a snarl of inefficiencies that don’t fit as neatly into the traditional purview of the IT department.
That’s because for every watt that a server in the typical datacenter consumes, another 1 to 1.5 watts are burned up by nonserver gear, says Jonathan Koomey, staff scientist at Lawrence Berkeley National Laboratory. To solve the problem, IT managers must address long-standing shortcomings in air-conditioning systems, power equipment, and other gear that has not traditionally been a responsibility of their department.