One of the things that impact the reliability of desktop and high capacity disk drives is their design duty cycle and usage patterns. For example, a typical enterprise class disk drive may be constantly spinning and subjected to sustained I/Os from multiple streams (applications and hosts). These types of disks are designed for these applications to support the rigors of that type of operation. On the other hand, desktop type disk drives are designed for a shorter duty cycle along with being spun up and spun down for power management.
Measuring the MBTF of a disk drive may not be a straight forward comparison. For example, an enterprise class disk may have an MBTF of over a million hours or about double that of desktop class disk drive. Another measure is to look at the number of hours the drives are actually in use compared with the time the disk drives are idle or spun down. In other words, look at the duty cycle time vs. the total elapsed time.
You can learn more about different disk drives and their interfaces from the SCSI Trade Association, the SATA industry trade association, and from disk drive manufacturers (Fujitsu, HGST, Maxtor, Seagate, Western Digital) Web sites.
This was first published in July 2005