The following metrics are reported as notifications:

• ceilometer_volume_total_capacity{pool="pool1"}
• ceilometer_volume_used_capacity{pool="pool1"}
• ceilometer_authenticate_success{user_id="123456"}
• ceilometer_authenticate_pending{user_id="123456"}
• ceilometer_authenticate_failure{user_id="123456"}

We could reenable events to get auditory of keystone logging events (and, at the same time, total disk capacity reporting).