This is what I thought amelius' comment was originally about. You could save power on drives plus it would only take a few seconds to come back online. I imagin

This is what I thought amelius' comment was originally about. You could save power on drives plus it would only take a few seconds to come back online. I imagine it could save a lot of electricity if the additional complication is worth it. Complications like a write cache drive in case of power failure, or grouping expected-cold data together. Also I wonder if powering the drive up and down occasionally will have a positive or negative impact on drive reliability compared to having it on 100% of the time.