ABSTRACT
This chapter begins with key metrics of the hard disk drive (HDD): price, performance, power, and capacity. It addresses operational improvements and reviews new system architectures with variations. In the real world, enterprise storage is about the balance of adequate performance, adequate capacity, adequate reliability, and data protection, all at the best possible price. There are data center professionals who have serious reservations regarding the reliability of high-capacity drives in the enterprise as well as regarding the use of serial advanced technology attachment as an enterprise drive interface. Queuing logic is referred to as “the elevator algorithm.” There are two very distinct classes of enterprise hard drives: performance optimized and capacity optimized. To improve caching and reliability, HDD write caching on HDDs should be turned off for enterprise applications, because if power is abruptly lost the data sitting in cache pending write to platter will be lost.
