So I logged into a new Amazon EC2 instance created with one of their new "standard" AMI's. Instead of seeing /dev/sda1 I see /dev/xvda1 . This relates to Xen somehow.
Here's what I can find that mentions this:
It says: "Apply the following patch to disable XSAVE". (someone must have done that before building the standard AMI)
Then it says: "Note that the root device here is /dev/xvda1 instead of /dev/sda1. This is caused by the XSAVE patch."
And finally it says: "Note that the devices here are /dev/sda1 and not /dev/xvda1. That is a little confusing but the AWS system doesn't see the devices in the same way your AMI will once it is booted."
Yes, it is kind of confusing and I would like to understand it.
Googling XSAVE and XVDA1 are not helpful at all.