I fail to see your point about the threshold of replacement. Assuming that enterprise-class drives get replaced sooner because sysadmins monitor SMART, it is still widely acknowledged that SMART errors are a strong indicated that the drive will fail soon. For example the Google study on drive reliability showed this correlation on consumer-class drives [1] There is no reason to believe this correlation doesn't exist with enterprise-class drives (or else, what would be the point of SMART?). Therefore the replacement threshold is mostly irrelevant as the enterprise drive replaced due to SMART would have failed soon anyway.
I really don't understand this skewed perception of consumer- vs enterprise-grade harddrives. Do you believe that enterprise CPUs are more reliable than consumer CPUs? How about enterprise NICs vs consumer NICs?
Consumer-grade drives are sold in volumes so much larger than enterprise-grade drives, that vendors have strong incentives to make them as reliable as possible. I would even say they have incentives to make them more reliable than enterprise-grade drives. Because a single percentage point improvement in their reliability will drastically reduce the costs associated to warranty claims and repairs.
My own experience confirms the CMU study. I have worked at 2 companies selling each about 2-5 thousand drives as part of appliances, to customers across the world. One company was using SCSI drives, the other IDE/SATA. And the replacement rates were similar.
I can see your point about the usage being different which could invalidate the CMU findings about consumer vs enterprise drive reliability. But I don't personally believe it explains it. The CMU study + my annecdotal evidence one 2-5 thousand drives + the fact that no study has ever showed data suggesting enterprise drives are more reliable, makes me think that they are not.
I really don't understand this skewed perception of consumer- vs enterprise-grade harddrives. Do you believe that enterprise CPUs are more reliable than consumer CPUs? How about enterprise NICs vs consumer NICs?
Consumer-grade drives are sold in volumes so much larger than enterprise-grade drives, that vendors have strong incentives to make them as reliable as possible. I would even say they have incentives to make them more reliable than enterprise-grade drives. Because a single percentage point improvement in their reliability will drastically reduce the costs associated to warranty claims and repairs.
My own experience confirms the CMU study. I have worked at 2 companies selling each about 2-5 thousand drives as part of appliances, to customers across the world. One company was using SCSI drives, the other IDE/SATA. And the replacement rates were similar.
I can see your point about the usage being different which could invalidate the CMU findings about consumer vs enterprise drive reliability. But I don't personally believe it explains it. The CMU study + my annecdotal evidence one 2-5 thousand drives + the fact that no study has ever showed data suggesting enterprise drives are more reliable, makes me think that they are not.
[1] http://static.googleusercontent.com/external_content/untrust...