Radical energy savings method 5: Use SSDs for highly active read-only data setsSSDs have been popular in netbooks, tablets, and laptops due to their speedy access times, low power consumption, and very low heat emissions. They're used in servers, too, but until recently their costs and reliability have been a barrier to adoption. Fortunately, SSDs have dropped in price considerably in the last two years, making them candidates for quick energy savings in the data center -- provided you use them for the right application. When employed correctly, SSDs can knock a fair chunk off the price of powering and cooling disk arrays, with 50% lower electrical consumption and near-zero heat output.
One problem SSDs haven't licked is the limited number of write operations, currently around 5 million writes for the single-level-cell (SLC) devices appropriate for server storage. Lower-cost consumer-grade multilevel-cell (MLC) components have higher capacities but one-tenth of SLCs' endurance.
The good news about SSDs is that you can buy plug-compatible drives that readily replace your existing power-hungry, heat-spewing spinners. For a quick power reduction, replace large primarily read-only data sets, such as streaming video archives, with SSD. You won't encounter SSD wear-out problems, and you'll gain an instant performance boost in addition to reduced power and cooling costs.
Go for drives specifically designed for server, rather than desktop, use. Such drives typically have multichannel architectures to increase throughput. The most common interface is SATA 2.0, with 3Gbps transfer speeds. Higher-end SAS devices, such as the Hitachi/Intel Ultrastar SSD line, can achieve 6Gbps speeds, with capacities up to 400GB. Although SSD devices have encountered some design flaws, these have been primarily with desktop and laptop drivers involving BIOS passwords and encryption, factors not involved in servers' storage devices.
Do plan to spend some brain cycles monitoring usage on your SSDs, at least initially. Intel and other SSD makers provide analysis tools that track read and write cycles, as well as write failure events. SSD disks automatically remap writes to even out wear across a device, a process called load leveling, which can also detect and recover from some errors. When actual significant write failures begin occurring, it's time to replace the drive.