Distributed caching system for multi-site DPM storage

The main goal of this work, in the context of WLCG, is to test a storage setup where the storage areas are geographically distributed and the system provides some pools behaving as data caches. Users can find data needed for their analysis in a local cache and process them locally. We first demonstrate that the distributed setup for a DPM storage is almost transparent to the users, in terms of performance and functionalities. Then, we implement a mechanism to fill the storage cache with data registered in Rucio Data Management system and we test it, running a physics analysis that gets its input data from the cache. Thus we demonstrate that the use of such a system can be useful for diskless sites with a local cache only, allowing to optimize the distribution and analysis of experimental data.