ATLAS DQ2 Deletion Service

The ATLAS Distributed Data Management project DQ2 is responsible for the replication, access and bookkeeping of ATLAS data across more than 100 distributed grid sites. It also enforces data management policies decided on by the collaboration and defined in the ATLAS computing model. The DQ2 deletion service is one of the most important DDM services. This distributed service interacts with 3rd party grid middleware and the DQ2 catalogs to serve data deletion requests on the grid. Furthermore, it also takes care of retry strategies, check-pointing transactions, load management and fault tolerance. In this paper special attention is paid to the technical details which are used to achieve the high performance of service (peaking at more than 4 millions files deleted per day), accomplished without overloading either site storage, catalogs or other DQ2 components. Special attention is also paid to the deletion monitoring service that allows operators a detailed view of the working system.