3 ms·
How common DRAM errors are is very unclear. The numbers in that paper are astronomically high, but other sources have published numbers that are 30x or 100,000x
by jules 15y ago
How common DRAM errors are is very unclear. The numbers in that paper are astronomically high, but other sources have published numbers that are 30x or 100,000x or literally 10,000,000x lower.
See this Stanford ee380 talk: http://stanford-online.stanford.edu/courses/ee380/100922-ee380-300.asx http://stanford-online.stanford.edu/courses/ee380/100922-ee3...
The part about DRAM errors is about 57 minutes in.
Abstract here: http://www.stanford.edu/class/ee380/Abstracts/100922.html http://www.stanford.edu/class/ee380/Abstracts/100922.html
Also, AFAIK most hosting providers don't even have ECC ram as an option for servers, e.g. Amazon.
- justincormack 15y agoDo you have a source on Amazon not using ECC?
- jules 15y agoI was not able to find Amazon declaring that they don't, but neither do they say anywhere that they do. For example they describe the hardware specs here: http://aws.amazon.com/ec2/instance-types/ http://aws.amazon.com/ec2/instance-types/ If they did have ECC RAM it is unlikely that they would keep it secret, especially given that ECC RAM can be twice as expensive.
- EwanToo 15y agoI don't think there's a confirmed source, but there's certainly indications, for example, an AWS post that they use ECC memory for the GPUs in their cluster GPU instance http://aws.typepad.com/aws/2010/11/new-ec2-instance-type-the-cluster-gpu-instance.html http://aws.typepad.com/aws/2010/11/new-ec2-instance-type-the... Given that they list both the standard memory and GPU memory next to each other, but only put ECC next to the GPU memory, it seems relatively likely to me that the standard server memory is not ECC.
- justincormack 15y agoBut Nvidia only sell Tesla's with ECC. I don't really read that implication into this. On the other hand, the fact that https://forums.aws.amazon.com/message.jspa?messageID=203167 https://forums.aws.amazon.com/message.jspa?messageID=203167 has never been answered suggests they do not, as they would answer affirmatively if it was true surely. Of course they may use a mixture. EDIT: Interesting that James Hamilton is on their team and thinks they should use it http://perspectives.mvdirona.com/2009/10/07/YouReallyDONeedECCMemory.aspx http://perspectives.mvdirona.com/2009/10/07/YouReallyDONeedE...
- EwanToo 15y agoI can well imagine that newer machines have it, and older ones don't, and slowly over time they'll end up with everyone using ECC. The costs involved were a lot higher 3-5 years ago than they are today.
- wmf 15y agoAmazon uses Xeons and Opterons where ECC is pretty much mandatory. They don't have an option for ECC because all their servers have it.