Supporting Dynamic Migration in Tightly Coupled Grid Applications

In recent years, there has been a growing trend towards supporting more tightly coupled applications on the grid, including scientific workflows, applications that use pipelined or data-flow like processing, and distributed streaming applications. As availability of resources can vary over time in a grid environment, dynamic reallocation of resources is very important for these applications, particularly because of their long-running nature, and because they often require large-volume data transfers between processing stages. This paper considers the problem of supporting and efficiently implementing dynamic resource allocation for tightly-coupled and pipelined applications in a grid environment. We provide an alternative to basic checkpointing, using the notion of light-weight summary structure (LSS), to enable efficient migration. The idea behind LSS is that at certain points during the execution of a processing stage, the state of the program can be summarized by a small amount of memory. This allows us to perform low-cost process migration, as long as such memory can be identified by an application developer, and migration is performed only at these points. Our implementation and evaluation of LSS based process migration has been in the context of the GATES (grid-based adaptive execution on streams) middleware that we have been developing. We also present an algorithm for dynamic resource allocation, and have shown an architecture for resource monitoring and allocation. We have extensively evaluated our implementation using three stream data processing applications, and show that the use of LSS allows efficient process migration