Exoscale is the leading swiss cloud platform and provides computing to a large base of swiss and worldwide customers. To complement the public computing offering, a new S3 compatible object storage service will be launched in the near future. The goal of this project is to design the schema of a large distributed system built around Cassandra and release it as both the commercial offering for exoscale and as a standalone Open Source project. In particular, the student will design the schema of the Cassandra cluster, assess the performance and consistency across a large number of nodes and perform reliability testing.