The ATLAS experiment at the LHC collected huge amounts of data during its first data-taking run. These data are mostly records of particle interactions and a response produced in the detectors - an “Event”, both obtained in real collisions and in simulated software. Events are being processed in various stages on the Grid distributed computing network, and the results of this “data production” are stored in computing centers around the world. These data, corresponding to billions of events, have to be cataloged according to different points of view to meet multiple user cases and search criteria by various physics analysis groups. The currently used catalog, which uses the ORACLE database, has difficulties providing the necessary functionality and cannot be scaled to the dramatically increased amount of data in the upcoming Run-II at LHC. Thus, the new EventIndex system is being created, based on modern NoSQL technologies, that allow natural scaling and provide good performance, robustness and ease of use. It will be implemented in the Hadoop environment, which originates from Google development and ins currently being used by companies dealing with the largest data volumes, such as Yahoo and Amazon. Event index will contain just the basic information necessary to select events for analysis purposes: Event id, online trigger information and references to all files containing this event. An event record will be created when recording RAW data from the detector or HITS from Monte-Carlo generation, and new information will be added with every processing cycle, so the whole history of the event can be tracked. The system has to be ready in mid-2014 so that it can pass tests in the end of the next year and will be ready for the beginning of Run-II in 2015. The EventIndex project is divided into 4 major tasks: core architecture, data collection and storage, query services, and functional tests and operation. Currently the third task – query services mostly requires manpower. It does not require a deep physics knowledge and that’s why it can be considered a good project for informatics students, for example.