Verified in 5.6.4.0 Using this manual: https://access.redhat.com/documentation/en/red-hat-cloudforms/4.2/paged/installing-red-hat-cloudforms-on-amazon-elastic-compute-cloud-amazon-ec2/ I added appliance as ec2 instance with additional drive as /dev/sdb. Then I set up appliance to use /dev/sdb as internal database storage. Rebooted and then checked appliance and web ui. Both was working.
Since the problem described in this bug report should be resolved in a recent advisory, it has been closed with a resolution of ERRATA. For information on the advisory, and where to find the updated files, follow the link below. If the solution does not work for you, open a new bug report. https://rhn.redhat.com/errata/RHBA-2017-0474.html