The Deis :ref:`control-plane` makes use of Ceph to provide persistent storage for the :ref:`registry`, :ref:`database`, and :ref:`logger` components. The additional operational complexity of Ceph is tolerated because of the need for persistent storage for platform high availability.
Alternatively, persistent storage can be achieved by running an external S3-compatible blob store, PostgreSQL database, and log service. For users on AWS, the convenience of Amazon S3 and Amazon RDS make the prospect of running a Ceph-less Deis cluster quite reasonable.
Running a Deis cluster without Ceph provides several advantages:
- Removal of state from the control plane (etcd is still used for configuration)
- Reduced resource usage (Ceph can use up to 2GB of RAM per host)
- Reduced complexity and operational burden of managing Deis