The eXtreme DataCloud (XDC) project develops scalable technologies for federating storage resources and managing data in highly distributed computing environments. The provided services are capable of operating at the unprecedented scale required by the most demanding, data intensive, research experiments in Europe and Worldwide. The targeted platforms for the released products are the already existing and the next generation e-Infrastructures deployed in Europe, such as the European Open Science Cloud (EOSC), the European Grid Infrastructure (EGI), and the Worldwide LHC Computing Grid (WLCG). XDC is run by a Consortium that brings together technology providers with a proven long-standing experience in software development and large research communities belonging to diverse disciplines: Life Science, Biodiversity, Clinical Research, Astrophysics, High Energy Physics and Photon Science. The project grounds its roots on technologies already developed by the partners or previous H2020 initiatives (such as the INDIGO-DataCloud project). XDC software is released as Open Source and is based on already existing components that the project enriches with new functionalities and plugins. The use of standards and protocols widely available on the state-of-the-art distributed computing ecosystems guarantees that the released components can be easily plugged into the European e-Infrastructures and in general on cloud based computing environments. The project is investing in the direction of enhancing the user experience in accessing the data management services, providing friendly, web-based user interfaces ready for the mobile world. The final goal is to significantly lower the access barriers to distributed computing, release more usable, more reliable, functionality-rich and still scalable data management services to cope with the most demanding scientific use cases. XDC services are designed to cope with the new nature of the distributed e-infrastructure, providing solutions to support the dynamic extension of computing centers to remote locations or the usage of sites with limited storage capacity maintaining transparent bi-directional access to the data stored in all the locations. XDC opens new possibilities to scientific research communities in Europe supporting the evolution of e-Infrastructure services for Exascale data resources. The driving force of the project developments relies on real life requirements provided by the Research Communities represented in the Consortium, however the topics and challenges addressed are of general interest for bigger and smaller user communities. The main general impact expected for the project is an increased uptake of the European e-Infrastructures.
