John Spiers over at the LeftHand Networks has a blog post on how the company approaches power savings for SANs. Part of the overall efficiency story is in the company's provisioning software. The other is hardware:

In fact, all of LeftHand’s disk arrays now run on Intel multi-core processors. Our real industry advantage comes from the fact that LeftHand’s SAN/iQ is hardware agonistic, so we can bring advanced storage virtualization and management capabilities to the greenest storage platforms available.

LeftHand’s Storage Platforms also use the latest power-saving disk drive technology: reliable, inexpensive SAS drives, which consume less power and will, I believe, eventually replace all shared bus drive technology, including Parallel SCSI and Fibre Channel Arbitrated Loop. Typical power consumption for a Fibre Channel drive is 18.8 Watts, compared with 17.4 Watts for SAS drives based on disk drive specifications from the manufacturer. SAS drives also perform better – no shared SCSI buses, no arbitrated loop I/O contention, no more LIP storms or FC drive chatter – all dedicated, high speed point-to-point serial interconnects.

Check out the blog post for more insight, though obviously from a pro-LeftHand viewpoint.