Design and Implementation of a Middleware for Data Storage in Opportunistic Grids

Shared machines in opportunistic grids typically have large quantities of unused disk space. These resources could be used to store application and checkpointing data when the machines are idle, allowing those machines to share not only computational cycles, but also disk space. In this paper, we present the design and implementation of OppStore, a middleware that provides reliable distributed data storage using the free disk space from shared grid machines. The system utilizes a two-level peer-to-peer organization to connect grid machines in a scalable and fault- tolerant way. Finally, we use the concept of virtual ids to deal with resource heterogeneity, enabling heterogeneity- aware load-balancing selection of storage sites.