The success of PRACE in providing unprecedented allocations of resources for computational science projects of the highest scientific quality has identified challenges in the storage, analysis, visualization and transfer of data connected to large-scale simulations. In order to provide the best possible services to the scientific community and ensure the largest possible impact of these large-scale simulations, the PRACE Scientific Steering Committee (SSC) and the Board of Directors (BoD) of PRACE would like to get a better understanding of the challenges related to big data in connection with large scale simulations. The SSC invites Expressions of Interest for data services connected to large-scale computational projects, in order to better understand the level of demand, the scientific justification for such data services and the best way to structure these data services. The focus of the EoI is solely on data services that need to be tightly coupled to a PRACE computing system. Expressions of Interest should be submitted to eoi-bigdata@prace-ri.eu before 15 November 2013. The submissions should not exceed two pages (11pt Times New Roman, 1.5 cm margins) and should address the following points: 1. The scientific justification and why the handling of data must be closely integrated with the PRACE computing services. 2. Expected amount of data and time-frame for which the data must be accessible (both real-time and archived) at the PRACE computing resource, and expected computing resources needed for the analysis. 3. How the data will be managed and used. 4. Whether the data should/should not be open to the wider scientific community and how scientific access and accessibility/usability will be handled. 5. The transfer of data to/from the PRACE resource. Please note that submission of an Expression of Interest carries no implication regarding any allocation of resources or implementation of services. Kind regards Kenneth Ruud Chair of the PRACE Scientific Steering Committee (SSC) This information is also available on our web server http://www.lrz-muenchen.de/services/compute/supermuc/aktuell/ali4685/ Matthias Brehm