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ECC matters

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Re: ECC matters

#91
post #2

“ECC availability matters a lot - exactly because Intel has been instrumental in killing the whole ECC industry with it's horribly bad market segmentation.” Its. There, I finally corrected Linus Torvalds in something. :))

Maybe he composed the message using a machine with non-ECC RAM and suffered a bit flip, which through some chain of events, led to the ' being added. Best to give him the benefit of doubt, I think!

The mistake was that it was included.

Re: ECC matters

#92
ECC works if done right. Accessing a memory location can fix bit-flips (ECC is a 'correcting' code). But systems that don't regularly visit every memory location, can accumulate risk. Those dark corners of RAM can eventually get double-bit errors and be uncorrectable. So an OS might 'wash' RAM during idle moments, reading every location in a round-robin manner to get ECC to kick in and auto-correct. Doesn't matter how fast (1M every hour or whatever) as long as somehow ECC has a chance to work.

Re: ECC matters

#93

Earlier quoted context omitted.

Maybe he composed the message using a machine with non-ECC RAM and suffered a bit flip, which through some chain of events, led to the ' being added. Best to give him the benefit of doubt, I think!

The mistake was that it was included.

Oops, that was dumb. Fixed, thanks.

Re: ECC matters

#94
post #25

Earlier quoted context omitted.

There are situations though, where you’re working on a document and the documents “save” format is a memory dump. Corruption for things of that type (Adobe RAW for example) would remove data. It might present itself as a 1pixel colour difference, but it could be more damaging (incorrect finances, in accounting software for example). Software trusts memory; but memory can lie. That’s dangerous.

Those corner cases might occur rarely but are probably inconsequential given rate of occurrence versus rate of criticalness - it probably doesn't justify the markup for most. In a data center you're processing millions of transactions per minute so occurrence is much more impactful.

You need 1/8 more memory - that's real the cost. It's pretty much Intel's fault for the segmentation.

Re: ECC matters

#95
post #77

As someone who has had to read thousands of random game crash reports from all over the interwebs (you know when Windows says you might want to send that crash log? like that), I totally agree. Of all the things to be worried about, like OS bugs, bad hardware configuration, etc. bad memory is one of those really troubling things. You look at the code and say "it's can't make it here, because this was set" but when yo…

Do the crash reports include whether the machine has ECC memory?

Re: ECC matters

#96
post #90
post #25

Earlier quoted context omitted.

There are situations though, where you’re working on a document and the documents “save” format is a memory dump. Corruption for things of that type (Adobe RAW for example) would remove data. It might present itself as a 1pixel colour difference, but it could be more damaging (incorrect finances, in accounting software for example). Software trusts memory; but memory can lie. That’s dangerous.

To be fair, if your save mechanism is just a straight memory dump with no checksums and validation. You have bigger issues.

Why does it matter if it =HAD= checksum, the numbers would have been altered prior to save. It means you store one but you get two when read later. If the format calculates immediate checksums on blocks it'd detect memory corruption at best. The extreme downside is that such a part is untestable under normal conditions, hard to maintain, and it costs more than the ECC in development.

Re: ECC matters

#97
post #50

Earlier quoted context omitted.

To someone on HN who isn’t familiar with what Google does that explains nothing about how Google works ;)

Google is like an evil version of Duck Duck Go.

Nah, to Google is just a generic verb. For example I too do all my googling at Duck Duck Go.

Hi alphabet lawyers.

Re: ECC matters

#98
post #70

Earlier quoted context omitted.

Are there any Ryzen boards that support ECC and actually correct errors ?

quick search: https://rog.asus.com/forum/showthread.php?112750-List-Asus-M...

Most Ryzen ASRock boards support ECC as well. I'm happily using one right now.

Re: ECC matters

#99

ECC matters, even on the desktop, it's not even a discussion, to me. If you think it doesn't matter: how do you know? If you don't run with ECC memory, you'll never know if memory was corrupted (and recovered). That blue screen, that sudden reboot, that program crashing. That corrupted picture of your kid. Who knows. I'll tell you, who knows. God damn every sysadmin (or the modern equivalent) can tell you how often t…

I've got nearly 30 years of experience and not once has non ECC memory lead to corruption. Maybe a crash, maybe a panic, maybe a kernel dump... But.. in all my time operating servers over 3 decades, it's always been bad drivers, bad code and problematic hardware that's caused most of my headaches. Have i seen ECC error correction in logs? yeah.. I don't advocate against it but, i've found for most people you design a…

> if one crashes, so what

Crashes might not matter, but silent data corruption does. The owner/user of that data will care when they eventually discover that it at some point mysteriously got corrupted.

Re: ECC matters

#100
post #66

Earlier quoted context omitted.

I've considered using an AMD CPU instead of Intel's Xeon on the primary desktop computer, but even low-end Ryzen Threadripper CPUs have TDP of 180W, which is a bit higher than I'd like. And though ECC is not disabled in Ryzen CPUs, AFAIK it's not tested in (or advertised for) those, so one won't be able to return/replace a CPU if it doesn't work with ECC memory, AIUI, making it risky. Though I don't know how common i…

I don't think Threadripper is a hard requirement for ECC. There's some pretty reasonable TDP processors if you step down from Threadripper.

I haven't seen definite details and test results on these (but haven't looked recently).

What specific configurations (CPU, MB, RAM) are known to work?

Let's say I have a Ryzen system, how can I check if ECC really works? Like, can I see how many bit flips got corrected in, say, last 24h?

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