Evolution of the architecture of the ATLAS Metadata Interface (AMI)

The ATLAS Metadata Interface (AMI) is now a mature application. Over the years, the number of users and the number of provided functions has dramatically increased. It is necessary to adapt the hardware infrastructure in a seamless way so that the quality of service remains high. We describe the evolution from the beginning of the application life, using one server with a MySQL backend database, to the current state in which a cluster of virtual machines on the French Tier 1 cloud at Lyon, an Oracle database also at Lyon, with replication to Oracle at CERN and a back-up server are used.