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Hard Drive Reliability Update – Sep 2014

backblaze.com

41–50 of 168 posts

Re: Hard Drive Reliability Update – Sep 2014

#41

How times have changed; Seagate used to be (or at least have the reputation of being) the most reliable and Hitachi the least.

I'm so ashamed right now. I've been recommending Seagates to everybody who asked for years without updating my fundaments...

Re: Hard Drive Reliability Update – Sep 2014

#42
post #18

All my WD and Seagate drives have failed within two years of use. Call me the luckiest.

My small datacenter results mimic BackBlaze too. Dead/dying seagates all over the place. So I notified management that we will only be purchasing Hitachi drives from now on. I have a BackBlaze server that I recently converted to FreeBSD & ZFS. I love the drive-density that Backblaze offers but I HATE the lack of physical notification when a drive dies. Most ofther file-servers have a front-facing drive caddy, that us…

You definitely don't want to use drives from the same manufacturing run (batch) on the same array, since they are the most likely to fail all at the same time.

Second to that, you probably don't want to go single-source for your drives -- maybe use Hitachi with a mix of WD.

Re: Hard Drive Reliability Update – Sep 2014

#43
post #14

Since annual failure rate is a function mostly of age, it would be interesting to see a line chart of cumulative failure rate vs age. But since new drives are continually being added to the population, there would be fewer drives in the data set as you moved up each curve. I guess you could calculate confidence intervals at quarterly intervals, and so the error bars would get larger as age increases and 'n' decreases…

It's been 20 years since I took a reliability engineering class but I believe the go to curve is the negative exponential. Here is a link from a quick Googling:

http://www.quanterion.com/FAQ/Exponential_Dist.htm

Re: Hard Drive Reliability Update – Sep 2014

#44
post #29
post #15

Earlier quoted context omitted.

And thats whats weird, who is the audience for the article? I know what enterprise drive means and I know the author is smart and knows what it means, so why the weird implications in the article that have nothing to do with "enterprise"? For those not "in the know" the hardware is the same, but desktop firmware drives will sit there for 10 seconds or whatever it is beating the drive when there's a read (or write) fa…

Do you have any data to back up any of these claims? Because now I have a problem: should I believe guys who have been running 38 petabytes of storage for several years now and regularly present the data they gathered, or should I believe you?

I've read his blog posts before. He's a good author. I don't believe anything factual/technical in my post disagrees with reality or any of his historical posts.

I am open to the idea I'm misinterpreting how he presents enterprise vs consumer firmware loads. I assume its open knowledge that their secret sauce is using consumer hardware so assumptions about 15K fibre channel isn't relevant.

Re: Hard Drive Reliability Update – Sep 2014

#45

How times have changed; Seagate used to be (or at least have the reputation of being) the most reliable and Hitachi the least.

I think "times have changed" can be generalized into "times will change".

My experience has been that any rule about "brand X is the best" or "brand Y is the worst" only lasts for a short time--each hard drive technology "generation" seems to reshuffle the reliability matrix. Whoever was on top in 2009 has almost no bearing on who's on top in 2014, or who will be in 2019.

Re: Hard Drive Reliability Update – Sep 2014

#46
post #15

Biggest takeaway was at the end, with the "enterprise" drives being slightly less reliable than the consumer ones at half the cost.

And thats whats weird, who is the audience for the article? I know what enterprise drive means and I know the author is smart and knows what it means, so why the weird implications in the article that have nothing to do with "enterprise"? For those not "in the know" the hardware is the same, but desktop firmware drives will sit there for 10 seconds or whatever it is beating the drive when there's a read (or write) fa…

Are you claiming:

  o Enterprise and Consumer Drives are the Same Hardware.
  o Enterprise Firmware causes the drive to fail fast on physical errors 
    rather than endlessly retrying.
  o Enterprise Drives are more likely to be RMA'd?
Do you have any citations, evidence, reports, articles, white papers, research - anything (beyond random anecdotes, or miscellaneous blog entries) to back up these claims?

Re: Hard Drive Reliability Update – Sep 2014

#47

How times have changed; Seagate used to be (or at least have the reputation of being) the most reliable and Hitachi the least.

At some point, Hitachi Diskstars were referred to as "Death Stars", and that was all I knew about disk reliability. It is great to have some real information. Dell, Google, and Amazon can never write reports like this because the vendor relationship is important. Because these guys have no relationship and are buying consumer disks, the world finally gets brand level reliability reports. Kudos to Backblaze.

> Dell, Google, and Amazon can never write reports like this because the vendor relationship is important. Because these guys have no relationship and are buying consumer disks, the world finally gets brand level reliability reports. Kudos to Backblaze.

Dell maybe, but Google and Amazon consider what goes on in their data centers to be part of their secret sauce. It doesn't have to do with vendor relationships, it has to do with a competitive edge. Google and Amazon will drop a vendor without a second thought if it's even slightly more advantageous.

Re: Hard Drive Reliability Update – Sep 2014

#48
post #14

Since annual failure rate is a function mostly of age, it would be interesting to see a line chart of cumulative failure rate vs age. But since new drives are continually being added to the population, there would be fewer drives in the data set as you moved up each curve. I guess you could calculate confidence intervals at quarterly intervals, and so the error bars would get larger as age increases and 'n' decreases…

I'm not a statistician, but what you are describing is a situation in which the survival of the "subjects" (SSDs) is the crucial variable. How quickly the population declines is the question.

This is similar to studies in medical research, e.g., how long do subjects live after an experimental cancer treatment. What I've seen used is the Kaplan-Meier non-parametric method (Kaplan-Meier plot) for the purpose.

Maybe I'm just used to seeing these plots, but I find the method conveys information very effectively. More info can be found here: https://en.wikipedia.org/wiki/Kaplan%E2%80%93Meier_estimator

I agree that presenting the SSD life data in that way would be a good idea.

Re: Hard Drive Reliability Update – Sep 2014

#49
post #8

Biggest takeaway was at the end, with the "enterprise" drives being slightly less reliable than the consumer ones at half the cost.

Second takeaway: if you want working HDDs, go with Hitachi.

You are wrong.

The second takeaway is: Check the last Backblaze report right before you buy new drives.

Re: Hard Drive Reliability Update – Sep 2014

#50

How times have changed; Seagate used to be (or at least have the reputation of being) the most reliable and Hitachi the least.

Related: Intel's SSD is the only SSD I've ever lost data with. It happened due to a power outage that bricked the drive, and the only reason it happened was because of a flaw in their firmware, not their drive, which they hushed up. I was very surprised because Intel had the reputation of being the best SSD at the time. (It was the 300-something series.)
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