8 Ways To Reduce Server Power Consumption
Step 3: Stop Feeding The Hogs
New servers typically have some kind of control panel that displays power consumption and CPU utilization information, which makes it easy to compare efficiency.
Even if some of your servers don't have control panels you may still be able to make comparisons by reviewing the vendors' published power consumption ratings for servers at idle and at maximum CPU utilization.
Without a control panel or manufacturer ratings, you'll have to take the long way. First, get an idea of the machine's average CPU utilization using its system management software. For instance, in Windows call up the Control Panel, select Administrative Tools, and then Performance. It can give you an on-going average for CPU utilization.
Then, use an office-style electric meter to see how much power the machine is actually drawing (Turn to the last page of this guide to see information about selected power meters. These devices cost anywhere from $20 to $300, but you'll find many uses for them in your shop.) Remember, you'll have to power down each machine to plug it in through the meter, but as noted in Step 1: Flip The Off Switch, in most cases that won't be a problem.
Step 4: Virtualize Your Servers
After you gauge the power efficiency of your servers and determine which applications use a server only marginally, you can move the lightly used apps from under-employed or inefficient servers to a single server. Then you can pull the plug on other servers. This process relies on virtualization software, which lets multiple applications (and their operating systems) run on a single machine as if it's the sole occupant of that machine. Virtualization can often reduce the number of physical servers required by more than half.
Any server you virtualize should be high capacity, with multiple CPU cores, at least 4 GB of RAM, optical media, and more than 100 GB of disk storage. Most importantly, it should initially be a test machine rather than a production unit. Be sure to install and test everything before putting any newly virtualized applications into production.
Installing virtualization is getting easier, but still requires fairly broad computer literacy, as you will have to deal with such issues as IP addresses, virtual disks, virtual network interfaces, and file images. If a full-time IT staffer is not available, using a consultant might be advisable. For more on server virtualization using VMware, refer to bMighty's three-part series "How To Virtualize A Server," which walks you the entire process:
Step 5: Use Power-Management Software
Most server software includes power-saving options -- make it company policy to use these settings for all your servers. You can set your servers to shift automatically to low power after a period of inactivity; according to vendors, this setting alone can cut power consumption up to 20%.
Step 6: Buy Smart
Simply buying efficient hardware is, of course, half the battle. Begin by looking for devices that are certified to comply with the U.S. Government's Energy Star program which typically draw a quarter less power than those that don't comply. The program's specifications currently cover only servers derived from desktop machines, but preliminary Energy Star specifications for rack and blade configurations are expected in 2009.
Similarly, the 80-PLUS compliance program, sponsored by an industrial consortium, applies to the power supply circuitry inside desktops and servers (which convert AC to DC). 80-PLUS qualified units are at least 80 percent efficient at both high and low power levels; power delivery typically accounts for more than 50 percent of power consumption.
Certifications are only the beginning, chips matter, too. Consider investing in servers that use HE (High Efficiency) processors from AMD, and Intel's Low Voltage Xeon. And adding more RAM to your servers can cut power consumption by reducing the need for disk access -- hard drives use a third less power when they are not accessing data.
Just be careful about what type of memory chips you buy. Fully buffered DIMMs reportedly use about twice the power of DDR2 RAM and the extra throughput may not be worth the power penalty. And don't forget about hard drives. Newer, hard 2.5-inch form factor drives draw as little as one-sixth the power of older 3.5-inch hard drives, although they typically offer less storage capacity.
Finally, some companies try to economize by repurposing old desktops as servers. That may be penny smart but dollar foolish. Such machines often have components that are unnecessary in their new role yet continue to draw current. These include graphic accelerators, wireless cards, and extra optical drives. If you insist on reusing desktops, be sure to remove any unneeded components.