Group Consistency Model Which Separates the Intra-group Consistency Maintenance from the Inter-group Consistency Maintenance in Large Scale DSM Systems

According to the characteristics of large scale network computing systems, we proposed a group consistency model based on the concept of group to construct a DSM system. The novel model can use different inter-group and intra-group consistencies and lend itself to flexible, easily-managable, and application-suitable DSM in large scale systems. A group consistency model, which applies entry consistency among groups and lazy release consistency in a group, together with its implementation policy is discussed in this paper. It employs write-update and multiple-writer protocols in a group, and thus facilitates the simultaneous read and write in a group. The suitable protocols eliminate the false sharing and reduce the data acquiring time in a group. Furthermore, the inter-group consistency also suits the features of data sharing among groups and transmits the data modifications originated from a group in bulk to reduce the network traffic. In the end, an example using group consistency model is given and the trivial group consistency is discussed.