Using Amazon's AWS, I created a 1 GiB volume. I attached it to a running instance and formatted it with ext3. I then mounted it and and used
df -h to report its size. It's apparently 414G. I'm already using 2G of it.
What's going on here?
It could be that you tried to attach the volume to a device name that was already in use for ephemeral storage.
On some images I've used the boot device /dev/sda and /dev/sdb through /dev/sde is ephemeral storage. When I tried to attach an EBS volume as /dev/sdb I received no error from the AWS management console, but the volume did not attach on /dev/sdb.
Sounds like an error. :)
If you don't have any data on it, you might want to just ditch that volume and try again.