Data Replication in computer grids

Computer grids are collections of heterogeneous computer resources that work together to form a single system. Goal of that system is conducting difficult and data intensive scientific or technological calculations. This is achieved by sharing resources and data among different users and organizations. The special property of a grid system is that not only users, but also the resources are dynamically added and removed in the system. This may result in data unavailability. This is why a need for replication of data exists in grid systems. Data should be replicated in an automatic and seamless way to make the system more reliable, accessible and less sensitive to subsystem failures.