I have an EBS volume (e.g. /dev/sdf) that has been attached to an EC2 instance (which boots from a different EBS volume), and I have mounted the volume (through
/dev/sdf
Make an entry to /etc/fstab
/etc/fstab
Entry would be like:
/dev/sdf /data ext3 defaults 1 1
This will automatically mount the volume during reboot.