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ECC matters

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Re: ECC matters

#81

Post by jeffbee »

paulie_a wrote: post #41

There was a great defcon talk a while back regarding using ECC. The concept was called "dns jitter" Basically you can register domains using small bit differences for domains and start getting email and such for that domain If I recall correctly the example given was a variation of microsoft.com All because so much equipment doesn't use ECC

miclosoft.com is only one bit away from microsoft.com. Used to see these problems all the time when I worked on gmail.

At Google even with ECC everywhere there wasn't enough systematic error detection and correction to prevent the global database of monitoring metrics from filling up with garbage. /rpc/server/count was supposed to exist but also in there would be /lpc/server/count and /rpc/sdrver/count and every other thing. Reminded me daily of the terrors of flipped bits.

Re: ECC matters

#83

Post by vvanders »

defanor wrote: post #66
loeg wrote: post #33

Earlier quoted context omitted.

Yeah, it's real obnoxious of Intel to silo ECC support off into the Xeon line, isn't it? I switched to ECC memory in 2013 or 2014 with a Xeon E3 (fundamentally a Core i7 without the ECC support fused off) and of course a Xeon-supporting motherboard (with weird "server board" quirks: e.g., no on-board sound device). I love that AMD doesn't intentionally break ECC on its consumer desktop platforms and upgraded to the T…

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.

Re: ECC matters

#84

Post by johndough »

bitcharmer wrote: post #28
phh wrote: post #20

I don't know if ECC is that important, but reliability of RAM (or any storage) feels pretty crazy to me. 128GB being refreshed every second for a month error requires that the per-bit refresh process has a reliability of 99.9999999999999999% to be flawless. Considering we are dealing with quantum effects (which are inherently probabilistic), I wouldn't trust myself to design anything like that. Now back to ECC, I'll…

A system on Earth, at sea level, with 4 GB of RAM has a 96% percent chance of having a bit error in three days without ECC RAM. With ECC RAM, that goes down to 1.67e-10 or about one chance in six billions. So I'd say ECC is not only important but insanely impactful. There's a reason why many organizations don't even want to hear about getting rigs with non-ECC memory.

I ran a memory test for two weeks straight on a consumer laptop with 8 GB RAM and could not get a single bit flip, so your mileage may vary.

Re: ECC matters

#85

Post by andi999 »

simias wrote: post #13
raverbashing wrote: post #4

Earlier quoted context omitted.

Yeah I'm always annoyed with this kind of mistake. Especially as non-native speakers should know better than the native ones (which usually don't give a f.). Now the point about internally doing ECC is an interesting one, could be a way out of this mess. And apparently ECC is more available in AMD land

For a 2nd language speaker making these homophonic mistakes is actually a sign of fluency. It means that you just transcribe a mental flow of words instead of consciously constructing the language. The first time I wrote "your" instead of "you're" in English I thought it was quite a milestone!

Yes. I noticed this. When I was younger, I thought how can you mix up 'their, they're, there' people you do this must be the opposite of smart. This lasted for 4 years living in an English speaking country....

Re: ECC matters

#87

Post by sys_64738 »

dijit wrote: post #25
sys_64738 wrote: post #14

ECC memory is predominantly used in servers where failure absolutely must be identified and logged. The desktop market to a lesser extent due to lack of mission critical tasks being run from there.

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.

Re: ECC matters

#88

Post by erkkie »

touisteur wrote: post #6
raverbashing wrote: post #4

Earlier quoted context omitted.

Yeah I'm always annoyed with this kind of mistake. Especially as non-native speakers should know better than the native ones (which usually don't give a f.). Now the point about internally doing ECC is an interesting one, could be a way out of this mess. And apparently ECC is more available in AMD land

I think it's available for customer SKUs on AMD and not just for servers like in 'Xeon-land'... How I've wanted an ECC-ready NUC...

Probably not what you meant but https://ark.intel.com/content/www/us/en/ark/products/190108/... has support for Xeon (and ECC). Now how to actually practically source 32GB ECC enabled SO-DIMM sticks ..

Re: ECC matters

#89

Post by xxs »

bitcharmer wrote: post #34
freeqaz wrote: post #10

I bought ECC RAM for my laptop and it definitely was about 4x the price. It's valuable to me for a few reasons -- peace of mind being a big one. Bit flips happen and are real. I really wish ECC was plentiful and not brutally expensive!

This is the first time I hear about a laptop that supports ECC memory. Could you please share the make and model?

Lenovo has Xeon laptops[0], and technically Intel used to support ECC on i3 (and celeron, etc.)

0: https://www.lenovo.com/us/en/laptops/thinkpad/thinkpad-p/Thi...

Re: ECC matters

#90

Post by jkbbwr »

dijit wrote: post #25
sys_64738 wrote: post #14

ECC memory is predominantly used in servers where failure absolutely must be identified and logged. The desktop market to a lesser extent due to lack of mission critical tasks being run from there.

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.
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