Bamboo attaches only one EC2 instance store volume, even if more are available

Apropos JST-111251

We use c3.2xlarge instances in our Bamboo OnDemand configuration. According to http://aws.amazon.com/ec2/instance-types/ they're supposed to have 2x80GB SSD drives attached.

But when I run this script as root, I only see one of the disks.
[root@ip-10-190-10-84 ~]# df -lh
Filesystem Size Used Avail Use% Mounted on
/dev/xvda1 7.8G 4.1G 3.7G 53% /
devtmpfs 7.4G 16K 7.4G 1% /dev
tmpfs 7.4G 0 7.4G 0% /dev/shm
/dev/xvdb 79G 75G 0 100% /home

What we'd ultimately like is to mount both SSD drives in a "striped" RAID 0 configuration, and then setup the ephemeral storage structure on the striped logical disk. But at a minimum, we need the other SSD to be attached to the machine so we can use it at all.