Data management services of NorduGrid

In common Grid installations, the services responsible for storing big data chunks, replication of those data and indexing their availability are usually completely decoupled. And the task of synchronizing data is passed to either userlevel tools or separate services (like spiders) which are subject to failure and usually cannot perform properly if one of the underlying services fails too. The NorduGrid Smart Storage Element (SSE) was designed to try to overcome those problems by combining the most desirable features into one service. It uses HTTPS/G for secure data transfer, Web Services (WS) for control (through the same HTTPS/G channel) and can provide information to indexing services used in middlewares based on the Globus Toolkit . At the moment, those include the Replica Catalog and the Replica Location Service. The modular internal design of the SSE and the power of C++ object oriented programming allows one to add support for other indexing services in an easy way. There are plans to complement the SSE with a Smart Indexing Service capable of resolving inconsistencies hence creating a robust distributed data management system.