Slashdot Mirror
Disk Drive Failures 15 Times What Vendors Say
jcatcw writes "A Carnegie Mellon University study indicates that customers are replacing disk drives more frequently than vendor estimates of mean time to failure (MTTF) would require.. The study examined large production systems, including high-performance computing sites and Internet services sites running SCSI, FC and SATA drives. The data sheets for the drives indicated MTTF between 1 and 1.5 million hours. That should mean annual failure rates of 0.88%, annual replacement rates were between 2% and 4%. The study also shows no evidence that Fibre Channel drives are any more reliable than SATA drives."
The data sheets for the drives indicated MTTF between 1 and 1.5 million hours.
Yeah, but I bet they didn't say what planet those hours are on.
The theory of relativity doesn't work right in Arkansas.
We did both this study and the Google study in the first couple of days after FAST was over. Completely redundant....
...Carnegie Mellon researchers can't tell a mean from a median. This is inherently a long-tailed distribution in which the mean will be much higher than the median. Imagine a simple situation in which failure rates are 50%/yr, but those that last beyond a year last a long time. Mean time to failure might be 1000 years. You simply can't compare the statistics the way they have without knowing a lot more about the distribution than I saw in the article. Perhaps I missed it while skimming.
TFA seems surprised by SATA drives lasting as long as Fibre...why one earth would your data interface have any consequences on the drive internals? Or are we talking assuming Interface = Data Throughput?
I have had 3 personal use hard drives go bad in the last 5 years, they were either Maxtor or Wester Digital. I am not hard on the drives other than leaving them on 24/7. The drives that failed were all just for data backup and I put them in big, well ventilated boxes. With this use I would think the drives would last for years (at least 5 years), but nope! The drives did not arrive broken either, they all functioned great for 1-2 years before dying. The quality of consumer hard drives nowadays is way, WAY low, and the manufacturers should do something about it.
I don't consider myself a fluke because I know quite a few other people who have had similar problems. What's the deal?
Also, does anyone else find this quote interesting?:
"and may have failed for any reason, such as a harsh environment at the customer site and intensive, random read/write operations that cause premature wear to the mechanical components in the drive."
It's a f$#*ing hard drive! Jesus H Tapdancing Christ how can they call that premature wear, do they calculate the MTTF by just letting the drive sit idle and never reading and writing to it? That actually wouldn't suprise me.
Hey, there is only one Return and it's not of the King, it's of the Jedi.
"If they told me it was 100,000 hours, I'd still protect it the same way. If they told me if was 5 million hours I'd still protect it the same way. I have to assume every drive could fail."
Just common sense. It's "common sense," but not as useful as one might hope. What MTTF tells you is, within some expected margin of error, how much failure you should plan on in a statistically significant farm. So, for example, I know of an installation that has thousands of disks used for everything from root disks on relatively drop-in-replaceable compute servers to storage arrays. On the budgetary side, that installation wants to know how much replacement cost to expect per annum. On the admin side, that installation wants to be prepared with an appropriate number of redundant systems, and wants to be able to assert a failure probability for key systems. That is, if you have a raid array with 5 disks and one spare, then you want to know the probability that three disks will fail on it in the, let's say, 6 hour worst-case window before you can replace any of them. That probability is non-zero, and must be accounted for in your computation of anticipated downtime, along with every other unlikely, but possible event that you can account for.
When a vendor tells you to expect 1 0.2% failure rate, but it's really 2-4% that's a HUGE shift in the impact to your organization.
When you just have one or a handful of disks in your server at home, that's a very different situation from a datacenter full of systems with all kinds of disk needs.
Give me 6 month failure rates.
... 60 months? That would be the info that I'd need. Where's the big failure spike? I'm going to be replacing them right before that.
Start with 100 drives. Continuous usage.
How many fail in the first 6 months? 12 months? 18 months?
Slightly off-topic, but if you haven't checked the Self-Monitoring, Analysis and Reporting Technology (SMART) info provided by your drive to see if it is having errors, you probably should. You can download smartmontools, which works on Linux/Unix and Windows. Your Linux distro may have it included, but may not have the daemon running to automatically monitor the drive (smartd).
/dev/sda do: /dev/sda /dev/sda
:-)
To view the SMART info for drive
smartctl -a
To do a full disk read check (can take hours) do:
smartctl -t long
Sadly, I just found read errors on a 375-hour-old drive (manufacturer's software claimed that repair succeeded). Fortunately, they were on the Windows partition
What, really?
The same companies that lie about the capacity on EVERY SINGLE DRIVE they make? You don't think that they're a bunch of lying fucking weasels? (We're both using sarcasm here.)
I don't care how you spin it. 1024 is the multiple. NOT 1000!
Failure doesn't get fixed because making a drive more reliable means it costs more. If it costs more, it's not going to get purchased.
---
ECHELON is a government program to find words like bomb, jihad, plutonium, assassinate, and anarchy.
I thought storage-related redundancy was supposed to be a good thing ;)
After 12 years of running Internet servers, I won't put anything but Seagate SCSI drives in any mission critical servers. My experience indicates Seagate drives are superior. Who's the worst? Quantum. The only thing Quantum drives are good for is starting a fire IMO.
A good rule of thumb is 3 years. Most hard drives fail in 3 years. I dont know why, but im currently seeing alot of bad 2004 branded drives and consider that right on schedule. Last year the 02-03 drives were the ones failing left and right. I just pulled one this morning thats stamped march 04. Just started acting up a few days ago. Like clockwork.
I'll just use my special getting high powers one more time...
Before computers were used in real engineering, we could get away with "k" sometimes meaning 1024 (like in memory addresses) and sometimes meaning 1000 (like in network speeds). Those days are past. Now that computers are part of real engineering work, even the slightest amount of ambiguity is not acceptable .
Differentiating between "k" (=1000) and "ki" (=1024) is a sign that the computer industry is finally maturing. It's called progress.
A slashdotter who didn't build his own computer is like a Jedi who didn't build his own lightsaber.
Thats fair, but if you pull a bad drive, ghost it (assuming its not THAT bad), plop the new drive in, and the system works flawlessly, what are you to assume?
I dont really care to know exactly what is wrong with the drive. If i replace it, and the problem goes away, I would consdier that a bad drive. Even if you could still read and write to it. I just did one this morning that showed no symptoms other than windows taking what I considered a long time, to boot. All the user complained about was sluggish performance, and there were no errors or drive noises to speak of. Problem fixed, user happy, drive bad.
As I already posted, a good rule of thumb is 3 years from the date of manufacture, is when most drives go bad.
I'll just use my special getting high powers one more time...
Not that this is actually relevant or anything, but there's been a long-standing schism between the computing community and the scientific community concerning the meaning of the SI prefixes Kilo, Mega, and Giga. Until computers showed up, Kilo, Mega, and Giga referred exclusively to multipliers of exactly 1,000, 1,000,000, and 1,000,000,000, respectively. Then, when computers showed up and people had to start speaking of large storage sizes, the computing guys overloaded the prefixes to mean powers of two which were "close enough." Thus, when one speaks of computer storage, Kilo, Mega, and Giga refer to 2**10, 2**20, and 2**30 bytes, respectively. Kilo, Mega, and Giga, when used in this way, are properly slang, but they've gained traction in the mainstream, causing confusion among members of differing disciplines.
As such, there has been a decree to give the powers of two their own SI prefix names. The following have been established:
These new prefixes are gaining traction in some circles. If you have a recent release of Linux handy, type /sbin/ifconfig and look at the RX and TX byte counts. It uses the new prefixes.
Schwab
Editor, A1-AAA AmeriCaptions
0.88% != 0.88
0.0088 * 15 = 0.132 (13%)
13% you say? The excerpt says 2%-4%. RTA and you'll see though they report up to 13% on some systems.
...is that it detects SMART disk errors in normal use (i.e. you don't have to be watching the BIOS screens when your PC boots).
When I was trying the Vista RC, it told me that my drive was close to failing. I, of course, didn't believe it at first, but I ran the Seagate test floppy and it agreed. So I sent it back to Seagate for a free replacement.
About the only feature that impressed me in Vista, sadly. (And I'm not sure it should have impressed me, tbh. I'm assuming XP never did this as I've never seen/heard of such a feature.)
Well, the hard-drive makers are correct on the size thing - a Gigabyte is 1000 Megabytes, and the OS and software makers are wrong.
Yeah, they coined the term and have been using it for 40 years, but they're wrong.
Gigabytes are actually displayed as Gigabytes, or that the listing is changed to correctly display Gibibytes as the value? (or Kibibytes, Mebibytes, whatever)
Listen, just because someone comes up with a standard doesn't obligate everyone to use it, especially when they already have a perfectly workable system already. Claiming that NIST can impose an unwanted standard on the world is like saying that it isn't a word until the OED lists it.
"We returned the General to El Salvador, or maybe Guatemala, it's difficult to tell from 10,000 feet"
To clear up the confusion, the notation for binary, as in 2^20 bytes was developed. That would be a Mebibyte.
http://en.wikipedia.org/wiki/Mebibyte
yeah, I used to think they were dirty bastards, but they just work on a different scale than the rest of us.
The trick is to purchase your HD in pennies.
"100,000 pennies! why that's 1024 dollars!!"
ôó
Why do you think FORTRAN is one of the oldest computing languages in existence?
Because it was invented before most other computer languages? Is this a trick question ;-)
Except MTBF is just pulled out of their asses. Look at the development cycle of a hard drive. Look at the MTBF. I used to work for an engineering company, and have worked doing test suites to determine MTBF. Sure, there's numbers involved, but it's probably 60% wishful thinking and 40% science.
Believe me, they aren't determining an 11 year MTBF empirically.