A Fault Tolerance Scheme for Hierarchical Dynamic Schedulers in Grids

In dynamic grid environment failures (e.g. link down, resource failures) are frequent. We present a fault tolerance scheme for hierarchical dynamic scheduler (HDS) for grid workflow applications. In HDS all resources are arranged in a hierarchy tree and each resource acts as a scheduler. The fault tolerance scheme is fully distributed and is responsible for maintaining the hierarchy tree in the presence of failures. Our fault tolerance scheme handles root failures specially, which avoids root becoming single point of failure. The resources detecting failures are responsible for taking appropriate actions. Our fault tolerance scheme uses randomization to get rid of multiple simultaneous failures. Our simulation results show that the recovery process is fast and the failures affect minimally to the scheduling process.