I have large ec2 Ubuntu image and I'm just looking through the devices.

I noticed from the metadata that

%  curl http://169.254.169.254/latest/meta-data/block-device-mapping/ami
sda1
%  curl http://169.254.169.254/latest/meta-data/block-device-mapping/ephemeral0
sdb

However when I look what is actually mounted there is /dev/xvda1 and /dev/xvdb (and there is no /dev/sd* )

I know that both names look somewhat valid from the AWS documentation, but it looks to me from this like there is a mismatch in the instance metadata and what is actually on the machine.

Why don't they match?