backtop


Print 73 comment(s) - last by Chernobyl68.. on Mar 15 at 6:01 PM

Study says failure rates 15 times that of what manufacturers indicate

A study released this week by Carnegie Mellon University revealed that hard drive manufacturers may be exaggerating their mean-time before failure (MTBF) ratings on hard drives. In fact, researchers at Carnegie indicated that on the average, failure rates were as high as 15 times the rated MTBFs.

Rounding-up roughly 100,000 hard drives across a variety of manufacturers, researchers at Carnegie tested the drives in various operating conditions as well as real world scenarios. Some drives were at Internet services providers, others at large data centers and some were at research labs. According to test results, the majority of the drives did not appear to be affected by their operating environment. In fact, researchers indicated that drive operating temperatures had little to no effect on failure rates -- a cool hard drive survived no longer than one running hot.

The types of drives used in the study ranged from Serial ATA drives, SCSI and even high-end fiber-channel (FC) drives. Typically, customers will be paying a much larger premium for SCSI and FC drives, which also happen to usually carry longer warranty periods and higher MTBF ratings.

Carnegie researchers found that these high-end drives did not outlast their mainstream counterparts:
In our data sets, the replacement rates of SATA disks are not worse than the replacement rates of SCSI or FC disks. This may indicate that disk-independent factors, such as operating conditions, usage and environmental factors affect replacement rates more than component specific factors.
According to the study, the number one cause of drive failures was simply age. The longer the drive has been in operation, the more likely it will fail. According to the study, drives tended to start showing signs of failure after roughly five to seven years of service, after which there was a significant increase in average failure rates (AFR). The failure rates of drives that failed in their first year of service or shorter was just as high as those after the seven year mark.

According to Carnegie researchers, manufacturer MTBF ratings are highly overrated. Take for example the Seagate Cheetah X15 series, which has a MTBF rating of 1.5 million hours. This equates to roughly over 171 years of constant service before problems. Carnegie's researchers said however that customers should expect a more reasonable 9 to 11 years. Interestingly, real world tests in the study showed a consistent average failure of about six years.

The average replacement rate of drives ranged from 2-percent to a whopping 13-percent annually, indicating that there is a need for manufacturers to reevaluate the way a MTBF rating is generated. Worst of all, these rates were for drives with MTBF ratings between 1 million and 1.5 million hours.

Garth Gibson, associate professor of computer science at Carnegie indicated that the study was proof that MTBFs are not a reliable way of measuring drive quality. "We had no evidence that SATA drives are less reliable than the SCSI or Fiber Channel drives," said Gibson.

Carnegie researchers concluded that backup measures are a necessity with critically important data, no matter what kind of hard drive is being used. It is interesting to note that even Google's own data centers use mainly SATA and PATA drives. At the current rate, it is only a matter of time before SATA will perform equal or better than SCSI and FC drives, offering the same reliability, and for much less money.


Comments     Threshold


This article is over a month old, voting and posting comments is disabled

RE: Point is?
By JeffDM on 3/10/2007 10:24:00 AM , Rating: 2
I think flash drives may very well superscede hard drives in a decade. The cost per gigabyte of flash is going down a lot faster than with hard drives and that trend doesn't seem to be slowing down. I think it might require a change in how operating systems are written to make sure they don't need to swap.

During the transition, I think it's possible that the operating system, apps and critical data will reside on a flash drive, and less critical information will be on a separate volume that's on a hard drive. Maybe hard drives will still be around, but not everyone will need one. Power users will probably be the first to start using flash drives for computers, but will probably be the last to stop using hard drives too.


RE: Point is?
By TomZ on 3/10/2007 11:34:10 AM , Rating: 2
You have to look at two factors - cost and technology. On the cost side, there is an oversupply in the flash market right now, and so prices are pretty low. But it isn't always that way.

When you look at the technology, HDDs have a couple of orders of magnitude more storage capacity than flash, and R&D continues for HDDs as well as flash. So looking into the future, we would expect both to continue the trends of higher capacity, higher density, and lower cost per unit of storage.

So when flash can replace current HDDs in terms of cost and capacity for a mainstream market segment, HDDs will be also larger and cheaper than now. So I think what you'll see is HDDs continuing to hold marketshare until some other technology can totally dominate, e.g., the PRAM that Intel is talking about.


"If you can find a PS3 anywhere in North America that's been on shelves for more than five minutes, I'll give you 1,200 bucks for it." -- SCEA President Jack Tretton











botimage
Copyright 2014 DailyTech LLC. - RSS Feed | Advertise | About Us | Ethics | FAQ | Terms, Conditions & Privacy Information | Kristopher Kubicki