The JINR Tier1 Site Simulation for Research and Development Purposes

Distributed complex computing systems for data storage and processing are in common use in the majority of modern scientific centers. The design of such systems is usually based on recommendations obtained via a preliminary simulated model used and executed only once. However big experiments last for years and decades, and the development of their computing system is going on, not only quantitatively but also qualitatively. Even with the substantial efforts invested in the design phase to understand the systems configuration, it would be hard enough to develop a system without additional research of its future evolution. The developers and operators face the problem of the system behaviour predicting after the planned modifications. A system for grid and cloud services simulation is developed at LIT (JINR, Dubna). This simulation system is focused on improving the effciency of the grid/cloud structures development by using the work quality indicators of some real system. The development of such kind of software is very important for making a new grid/cloud infrastructure for such big scientific experiments like the JINR Tier1 site for WLCG. The simulation of some processes of the Tier1 site is considered as an example of our application approach.