5 ms·

I agree on the last part, and I think the particular weirdness here is a result of ZFS historically mentioning the value of ECC a lot more than other FSes. I th

by __jal 10y ago

I agree on the last part, and I think the particular weirdness here is a result of ZFS historically mentioning the value of ECC a lot more than other FSes. I think this probably makes people think that ZFS in some way depends on it more than others, rather than simply pointing out that there's a disturbingly high chance of encountering a problem without it that applies to everything. And sure, if you're building a frankenbox, ECC is probably not an option, or the sort of expense that takes it out of the frankenbox category. I do hope that folks wouldn't store important data on dodgy hardware, but that is about more than RAM, and also none of my business. I don't believe I'm misinterpreting people's reactions - I've witnessed people assert that ECC is a scam, waste of money and similar. Even after I point them to that link I posted above, they still seem to believe that It Won't Happen To Them. ("I don't have millions of machines.") In any case, I still find it frankly bizarre that people run the risk with important data. If you asked people if they wanted to buy a CPU that had an ~8% chance of undetectably lying to them, I'm pretty sure the vast majority would at least want to spring for the premium one that allows at the least detecting the lie.

wtallis 10y ago
> I've witnessed people assert that ECC is a scam, waste of money and similar. Even after I point them to that link I posted above, they still seem to believe that It Won't Happen To Them. ("I don't have millions of machines.") If by your own citation 92% of DIMMs operate with zero errors per year, and a consumer machine has at most four DIMMs, then it is actually pretty likely that any given consumer machine will operate without RAM errors even without ECC. And when you multiply by the low probability that a DRAM error will cause catastrophic data loss, then it is very easy to come to a reasonable conclusion that ECC is not worth the expense.
- __jal 10y ago
  Hey, it is your data. I personally don't like gambling with mine, but yours is none of my business. Again, I don't know how many people out there buy other products with a nearly 1 in 10 chance of undetectably not performing the function they are supposed to perform, but it seems nutty to me. Although that line of thought does go some way towards explaining the vitamin business...
  - wtallis 10y ago
    It's disingenuous of you to keep putting the error probabilities in terms like "nearly 1 in 10" without acknowledging the context that you're talking about the probability of a transient error occurring at any time over the course of a full year of continuous operation. Most people actually are comfortable with the idea that their equipment will have occasional downtime or faults, but you're trying to paint a very different picture.
    - __jal 10y ago
      Buddy, I would heartily encourage you to believe whatever you makes you happy. Your insult is false and petty, and I think you're pretty wrong about the rest of that. I personally consider it pretty disingenuous to call a fault that damages data on disk 'transient'. The root cause may have been transient, but the damage doesn't go away if/when a stuck bit functions normally again. Or do you consider a stroke leading to paralysis a transient injury? I'd also like to see a cite that "most people actually are comfortable with the idea that..." a 'transient' fault that scrambles random data they've chosen to keep. Where, exactly, are you getting this? Finally, assuming you have some actual basis for that claim, how many of those people run ZFS? You wouldn't conflate nontechnical people who buy the cheapest box at Best Buy with folks who take the time to configure software RAID across several disks using a nonstandard filesystem, would you?
- pixl97 10y ago
  >And when you multiply by the low probability that a DRAM error will cause catastrophic data loss, then it is very easy to come to a reasonable conclusion that ECC is not worth the expense. If your data is worth nothing, then ECC isn't worth the expense. That's part of the difference between more enterprise level and consumer level equipment. I do some work on my home computer, but I don't have ECC in it. I probably push a few terabytes of work related information over it a year. The rest is many more terabytes of movies and music, and other things that will never notice a bit error. At work where I move 10s of terabytes of information a day, and that information may have cost many hundreds of manhours to create, I use enterprise level memory, disks, and other parts. I've seen both servers and desktops develop bad ram. You want to know what the difference is when it happens? I get MCE logs from the server and we replace the equipment before anything bad happens. When it happens on the desktop you can end up with crashing programs, reboots, and even worse, corrupt data written to disk.
erkkie 10y ago
ZFS does depend on ECC more than other filesystems, in that it does data checksumming, which other filesystems (mostly) do not do. Those checksums can and will lie without ECC, in worst case rendering a data protective measure into a data losing measure.

by __jal 10y ago

wtallis 10y ago

> I've witnessed people assert that ECC is a scam, waste of money and similar. Even after I point them to that link I posted above, they still seem to believe that It Won't Happen To Them. ("I don't have millions of machines.") If by your own citation 92% of DIMMs operate with zero errors per year, and a consumer machine has at most four DIMMs, then it is actually pretty likely that any given consumer machine will operate without RAM errors even without ECC. And when you multiply by the low probability that a DRAM error will cause catastrophic data loss, then it is very easy to come to a reasonable conclusion that ECC is not worth the expense.

__jal 10y ago
Hey, it is your data. I personally don't like gambling with mine, but yours is none of my business. Again, I don't know how many people out there buy other products with a nearly 1 in 10 chance of undetectably not performing the function they are supposed to perform, but it seems nutty to me. Although that line of thought does go some way towards explaining the vitamin business...
- wtallis 10y ago
  It's disingenuous of you to keep putting the error probabilities in terms like "nearly 1 in 10" without acknowledging the context that you're talking about the probability of a transient error occurring at any time over the course of a full year of continuous operation. Most people actually are comfortable with the idea that their equipment will have occasional downtime or faults, but you're trying to paint a very different picture.
  - __jal 10y ago
    Buddy, I would heartily encourage you to believe whatever you makes you happy. Your insult is false and petty, and I think you're pretty wrong about the rest of that. I personally consider it pretty disingenuous to call a fault that damages data on disk 'transient'. The root cause may have been transient, but the damage doesn't go away if/when a stuck bit functions normally again. Or do you consider a stroke leading to paralysis a transient injury? I'd also like to see a cite that "most people actually are comfortable with the idea that..." a 'transient' fault that scrambles random data they've chosen to keep. Where, exactly, are you getting this? Finally, assuming you have some actual basis for that claim, how many of those people run ZFS? You wouldn't conflate nontechnical people who buy the cheapest box at Best Buy with folks who take the time to configure software RAID across several disks using a nonstandard filesystem, would you?
pixl97 10y ago
>And when you multiply by the low probability that a DRAM error will cause catastrophic data loss, then it is very easy to come to a reasonable conclusion that ECC is not worth the expense. If your data is worth nothing, then ECC isn't worth the expense. That's part of the difference between more enterprise level and consumer level equipment. I do some work on my home computer, but I don't have ECC in it. I probably push a few terabytes of work related information over it a year. The rest is many more terabytes of movies and music, and other things that will never notice a bit error. At work where I move 10s of terabytes of information a day, and that information may have cost many hundreds of manhours to create, I use enterprise level memory, disks, and other parts. I've seen both servers and desktops develop bad ram. You want to know what the difference is when it happens? I get MCE logs from the server and we replace the equipment before anything bad happens. When it happens on the desktop you can end up with crashing programs, reboots, and even worse, corrupt data written to disk.

erkkie 10y ago

ZFS does depend on ECC more than other filesystems, in that it does data checksumming, which other filesystems (mostly) do not do. Those checksums can and will lie without ECC, in worst case rendering a data protective measure into a data losing measure.