Patent ID: 8713280

Claim:
A system comprising: a controller; a plurality of hard disk drives connected to the controller, each hard disk drive selected from a plurality of different hard disk drive types, each hard disk drive type having a different speed at which the hard disk drives of the hard disk drive type rotate to read and write data, such that at least one of the hard disk drives is of a different hard disk drive type than at least one other of the hard disk drives; wherein prior to writing any data to the hard disk drives, the controller selects, from the plurality of hard disk drives and in accordance with one or more constraints, a set of hard disk drives to which data is to be written, such that the hard disk drives that are not selected are powered down; and responsive to a request to write particular data to the hard disk drives, the controller selects a given hard disk drive of the set of hard disk drives based on a type of the particular data, and writes the particular data to the given hard disk drive.