11–20 of 162 posts
"Ideally we would have some government action to force this given the ongoing cost to society in corrupted data" Why is it so often Australia with the "We must force unnecessary things upon people" attitude?
Interesting article, and I agree that ECC needs to be more widely available. But I think this is a major overreach: > We need ECC RAM to be more widely used. Ideally we would have some government action to force this given the ongoing cost to society in corrupted data and lost time due to RAM hardware errors. I think that at minimum we need sufficient taxes on non-ECC RAM (and EC4 RAM for DDR5) to make it more expens…
"Ideally we would have some government action to force this given the ongoing cost to society in corrupted data" Why is it so often Australia with the "We must force unnecessary things upon people" attitude?
"Ideally we would have some government action to force this given the ongoing cost to society in corrupted data" Why is it so often Australia with the "We must force unnecessary things upon people" attitude?
DDR5 on-die ECC detects and corrects one-bit errors. It cannot detect two-bit errors, so it will miscorrect some of them into three-bit errors. My understanding is that the on-die error correction scheme is specifically specially designed such that the resulting three-bit errors are mathematically guaranteed to be detected as uncorrectable two-bit errors by a standard full system-level ECC running on top of the on-die ECC. But I've never found a real authoritative reference that directly says that.
The problem I have with ECC discussions is that it’s always anecdotal. There is one Google study finding memory flips with some probability in their datacenters, but it was awhile ago. Everyone repeats the statement DDR5 on-die ECC isn’t a replacement for regular ECC, but nobody ever shows data on DDR5 bitflips. That’s not a knock on this article per se, but it’d be nice to have actual data here.
>> Everyone repeats the statement DDR5 on-die ECC isn’t a replacement for regular ECC, but nobody ever shows data on DDR5 bitflips. That's because the on-die ECC cannot detect errors in the transmission of data from the DIMMs to the CPU. It seems like on-die ECC is meant to "hide" some level of errors to make less reliable RAM chips appear good. I have no idea if that's a reasonable way to do it, but it seems like it…
Earlier quoted context omitted.
> ECC RAM is not needed for every application and mandating it for every gaming rig and machine used to run Chrome will just increase prices unnecessarily. The price increase will be very small if manufacturers are no longer able to segment the market to make a higher margin on those who need it. No one wants even games or web browsers to crash randomly. > If they want to eat that cost, it should be up to them. They…
Without quantifying the cost to society that someone's web-browser crashes sometimes, it's hard to make a rational case that this issue is so dire that it needs specific regulation. I'm not sure making it illegal to sell consumer grade hardware is the boon for the people you imagine
https://ripe92.ripe.net/programme/meeting-plan/sessions/112/...
Earlier quoted context omitted.
>> Everyone repeats the statement DDR5 on-die ECC isn’t a replacement for regular ECC, but nobody ever shows data on DDR5 bitflips. That's because the on-die ECC cannot detect errors in the transmission of data from the DIMMs to the CPU. It seems like on-die ECC is meant to "hide" some level of errors to make less reliable RAM chips appear good. I have no idea if that's a reasonable way to do it, but it seems like it…
Right. Everyone agrees that real ECC is more robust, and production servers of course run it. But it seems to me that if most RAM bitflips are in the module itself (rather than in transmission to CPU), then on-die ECC could in theory make the probability of a bitflip in practice so low that for things like home servers it isn’t worth the price premium for real ECC. But without data on this, everyone is just speculati…
Got ECC udimm for my ddr4 server and was surprised to see it picking up errors occasionally (once every couple months). Likely from a weakness in one of the sticks. This far it’s always corrected it though so opted to keep them anyway (nobody wants to be minus 32gb in these trying memory times) With normal sticks I’d not have know that there is a potential issue.
The problem I have with ECC discussions is that it’s always anecdotal. There is one Google study finding memory flips with some probability in their datacenters, but it was awhile ago. Everyone repeats the statement DDR5 on-die ECC isn’t a replacement for regular ECC, but nobody ever shows data on DDR5 bitflips. That’s not a knock on this article per se, but it’d be nice to have actual data here.
When you do not own a great number of servers, you cannot provide anything else except anecdotal evidence.
Because the vast majority of PCs do not have ECC memory, even the companies that have a great number of PCs have no idea about the reliability of the memory used in those PCs, because it is very difficult to distinguish memory defects from the huge number of software bugs.
Moreover, the frequency of memory errors is proportional with the amount of memory you have, so those with tiny amounts of memory, like 8 GB, are much less likely to encounter memory errors than those who have 32 GB or 64 GB of DRAM in their PCs.
I have tried to always use ECC memory in my computers, whenever possible. Even my laptop is an older Dell Precision, with ECC memory.
But I can also offer only anecdotal testimony.
I have also seen cases like that mentioned in TFA, where the existence of ECC allowed to discover that some modules were not seated well in their sockets, so reseating them prevented the reappearance of errors.
I have also seen a case when a laptop was not used for a long time and it was stored in a rather humid place, so the contacts in the SODIMM sockets had oxidized, which resulted in frequent memory errors. Scrubbing vigorously the contacts and reinserting the memory modules solved the problem.
I have also seen many cases where certain memory modules degraded after many years of use, e.g. 5 or more years of 24/7 use, and they began to have frequent errors, e.g. multiple errors per day, even if when they were new the error rate could have been of one error per year or even less.
In such cases ECC was extremely useful, because the DIMM that had become worn out could be identified and replaced and the server could work fine some more years.