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A comment on Best CPUs for Workstations. Parent comment

Re:Best CPUs for Workstations by littlestymaar on Tuesday May 05, 2020 @07:14AM (#23078744)
> No ECC, though.

Is ECC useful for a workstation? I thought it was useful for shared servers (VM hosts) to protect against rowhammer & co, but does is have other uses?

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Re:Best CPUs for Workstations by lazyjones on Tuesday May 05, 2020 @07:29AM (#23078848)
http://cr.yp.to/hardware/ecc.html

Without ECC, modern systems (>= a few GB RAM) will have bits flipping pretty much daily.

https://news.ycombinator.com/item?id=1109401

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Re:Best CPUs for Workstations by agapon on Tuesday May 05, 2020 @11:22AM (#23080964)
This does not seem to be true in practice. I use ECC on my systems and they are configured to log any ECC error. And I see ECC erros almost never. Mostly ECC errors start appearing on very old systems when something in hardware becomes bad because of the age (even if just oxidized contacts). I am not sure if I've ever seen a truly random ECC error.
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Re:Best CPUs for Workstations by jeffbee on Tuesday May 05, 2020 @02:50PM (#23083390)
What do you mean by "very old"? This study, which is the only comprehensive public data of which I am aware, says that onset of DRAM errors occurs after 10-18 months.

https://storage.googleapis.com/pub-tools-public-publication-...

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Re:Best CPUs for Workstations by LargoLasskhyfv on Wednesday May 06, 2020 @01:51AM (#23088234)
I've read such studies with great interest, and i prefer ECC whenever possible, but i think these don't necessarily apply to desktops, at least partially.

I think the environment in racks for nodes in whichever formfactor in racks is toxic. Be it EMF interference, power distribution issues, vibrations, and/or temperature. You don't have that in a single system at home, when it is built in a good way, and has stable power. Or at least to a lesser degree.

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Re:Best CPUs for Workstations by agapon on Wednesday May 06, 2020 @05:33AM (#23089253)
Very old -- like 10+ years old.
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Re:Best CPUs for Workstations by jleahy on Tuesday May 05, 2020 @10:45AM (#23080538)
It's not quite fair to just extrapolate numbers for 256MB of RAM up to a modern system. If this was true you'd be seeing OS crashes daily (if you run hundreds of servers with no ECC you will see mysterious crashes every day, but for one server it might be once a year).

Ultimately these flips are caused by charged particles hitting the memory module (a so called 'single event upset' or SEU), and the number of charged particles hitting the modules has not increased with density (although the modules are more sensitive to SEU, it's a smaller effect).

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Re:Best CPUs for Workstations by vbezhenar on Tuesday May 05, 2020 @11:23AM (#23080975)
To encounter a crash, bit flip has to happen on a very small subset of available memory. It's much more likely to just corrupt file cache.
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Re:Best CPUs for Workstations by jleahy on Tuesday May 05, 2020 @03:29PM (#23083869)
Well it depends what you're doing, if your memory is full of hash tables and linked lists then you'll likely get a crash (say a web backend). If you're a fileserver and it's all cache then you won't.
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Re:Best CPUs for Workstations by tpetry on Tuesday May 05, 2020 @07:34AM (#23078891)
Itβ€˜s usefull for everyone but bit errors happen far far seldom than people do expect. But you should have it just in case. You dont want e.g. a corrupt database file just because the low probability of a bitceroor happened and you have been in bad lick it was on a very critical operation.
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Re:Best CPUs for Workstations by vardump on Tuesday May 05, 2020 @07:40AM (#23078938)
> ...bit errors happen far far seldom than people do expect.

Until they happen more often that expected. It's something that varies based on building, temperature, etc. environmental factors. And of course on your luck with memory module lottery.

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Re:Best CPUs for Workstations by vardump on Tuesday May 05, 2020 @07:22AM (#23078790)
Yeah, ECC makes the system much more reliable. It drives those weird unexplained glitches away.
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Re:Best CPUs for Workstations by jeffbee on Tuesday May 05, 2020 @02:47PM (#23083352)
According to this paper, 8% of DIMMs and 32% of machines suffered from at least one correctable error per year. Without ECC, that's an undetected and uncorrected error. The average machine in the study had over 22,000 corrected errors per year. The paper observes that "memory errors are not rare events". If you're running without ECC, you are quite likely to have some undetected corruption, which could range from a single erroneous bit over the lifetime of the machine all the way up to constant unexplained crashes and file or filesystem corruption. There are plenty of use cases where it doesn't matter but for workstation use you presumably care about the results.

https://storage.googleapis.com/pub-tools-public-publication-...

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Re:Best CPUs for Workstations by 83457 on Tuesday May 05, 2020 @07:30AM (#23078856)
It prevents corruption from bit flips caused by cosmic rays and other sources. More important for scientific/business purposes and at higher altitudes where there is less atmosphere to block cosmic rays.
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