Grid accounting records usage of Grid resources by users and groups of users (e.g Virtual Organizations). Accounting information can be used to charge users for the Grid resources they have utilised. The information available from the accounting service can also be used to implement submission policies based on user quotas or on resource usage (fair share). In principle it also allows the creation of a real exchange market for the Grid resources and services. The subsequent economic competition should result in market equilibrium, thereby promoting load balancing on the Grid.
DGAS (Distributed Grid Accounting System) is the accounting system deployed in the Italian Grid Infrastructure. DGAS provides the functionality needed for the implementation of a complete infrastructure for computing and storage accounting of national Grids and Grid Virtual Organizations. It provides sensors for many different Local Resource Management Systems, repositories for persistent storage of usage records at site-level or national/regional-level and it comes along with a tool, called HLRMon, which provides a user-friendly web-based interface to display the accounting data. DGAS and HLRmon are supported by the INFN Grid and EGEE projects.