During the last couple years, he has had to deal with some applications using large databases that require scalability and high availability. A few years ago, Jean had learned about NoSQL and did a large study about a few NoSQL databases (Cassandra, MongoDB, HBase, Hypertable, Riak, …). This study focused on performances, robustness, scalability and exploitability. At the end of his study, Orange decided to replace the relational databases (Postgres and Mysql cluster) with Apache Cassandra for the application PnS, in order to sustain growth in requests and volume of data. PnS is a highly available and critical service for collecting and serving live data about Orange customers.