Not in the article. On the EC2 website: http://aws.amazon.com/ec2/instance-types/

Specifically, the new instances (m3.*) are only available with ebs. There is probably a technical reason for this - eg maybe they move these bigger instances around to different servers so they can't be on local disk? Would love to know why...

I'm guessing that Amazon has wanted to phase out ephemeral disk on non-HPC instances for a long time, since it costs them money and most people don't use it; and the availability of EBS-optimized instances and provisioned-IOPS disks was what they needed to satisfy the people who insisted that ephemeral disk was the only way to get reliable I/O performance.

And I'm sympathetic to that argument where large amounts of disk are concerned... but I do wish we could have a small amount of ephemeral disk to be used for swap space.

I think there's a reliability argument to be made as well. Most (all?) of the EC2 outages and partial outages over the past year or so have had their root cause somewhere in EBS. It's also why I hesitate to touch ELBs or RDS, since they both rely on EBS.

My guess is that ephemeral disks were dropped because of too many people losing data on them.

Not because of a fault, but because they don't know instance disks are ephemeral.

Permanent storage as a default is a saner default as well.

I think it's moot. For heavy users, the use case for ephemeral disk is better served by their I/O instances. For light users, I think Amazon is betting that EBS is 'stable enough' by now. If you really don't like EBS, there's always the old instances, Amazon RDS, Amazon DynamoDB...