~okeanos: Large-Scale Cloud Service Using Ceph

~okeanos is a large-scale public cloud service powered by Synnefo and run by GRNET. Ceph is a distributed storage solution that targets scalability over commodity hardware. This article focuses on how we use Ceph to back the storage of ~okeanos. More specifically, we will describe what we aimed for in our storage system, the challenges we had to overcome, certain tips for setting up Ceph, and experiences from our current production cluster.