A lot of marketing effort has been thrown at the concept of green computing and sustainable IT, but much of the advice is fairly nebulous, fuzzy and ill thought out.
However, if you can make it past the greenwash, there are some practical tips IT departments can follow that should result in lower running costs and hopefully more sustainable approaches to data-centre management.
1. Consolidate servers using virtualisation. It also reduces the number of servers and increases utilisation rates.
2. Power-supply efficiencies for servers purchased more than 12 months ago typically range from 55 percent to 85 percent. That means 15 percent to 45 percent of incoming power is wasted before it hits the IT load. Newer servers operate at 92 percent or 93 percent efficiency, and most don't drop below 80 percent, even at lower utilisation levels.
3. Using networked storage can also reduce energy costs. An IBM BladeCenter with 56 blades, for example, can use 1.2 kilowatts of power. Replacing them with a single 12-disk Serial Attached SCSI storage array could use less than 300 watts.
4. Don't forget the basics. Check for airflow blockages under the floor or leaks in the racks, which will drive up the need for airflow.
5. Insert blanking plates, make sure those you already have are in the right place.
6. Consider raising the temperature a few degrees. If the weather is cold outside, design air-conditioning systems that can take advantage of external air.
7. Use variable-speed fans. Most air-conditioning fans run at 100 percent cycle and have one speed, but a dynamic fan can use temperature sensors to increase and decrease fan speeds as needed.
8. UPSs are often over-sized and older models may not be designed to run efficiently for low utilisation rates.
9. Consider how you store data. Optical storage is highly energy-intensive, so store data on tape or offline wherever possible.
10. If you're building a new data centre, consider investing in energy-friendly features such as motion detectors to turn off lighting when nobody is working, and recycled water collection systems for backup cooling.
