Job-Site Level Fault Tolerance for Cluster and Grid environments

In order to adopt high performance clusters and grid computing for mission critical applications, fault tolerance is a necessity. Common fault tolerance techniques in distributed systems are normally achieved with checkpoint-recovery and job replication on alternative resources, in cases of a system outage. The first approach depends on the system\´s MTTR while the latter approach depends on the availability of alternative sites to run replicas. There is a need for complementing these approaches by proactively handling failures at a job-site level, ensuring the system high availability with no loss of user submitted jobs. This paper discusses a novel fault tolerance technique that enables the job-site recovery in Beowulf cluster-based grid environments, whereas existing techniques give up a failed system by seeking alternative resources. Our results suggest sizable aggregate performance improvement during an implementation of our method in Globus-enabled HA-OSCAR. The technique called \´\´smart failover" provides a transparent and graceful recovery mechanism that saves job states in a local job-manager queue and transfers those states to the backup server periodically, and in critical system events. Thus whenever a failover occurs, the backup server is able to restart the jobs from their last saved state