March 2003

Distributed systems require strategies to detect and recover from failures. Many protocols for distributed systems employ a strategy based on leases, which grant a leaseholder access to data or services for a limited time (the lease period). Choosing an appropriate lease period involves tradeoffs among resource utilization, responsiveness, and system size. We investigate these issues for Jini Network Technology. First, we establish quantitative tradeoffs among lease period, bandwidth utilization, responsiveness, and system size. Then, we consider two self-adaptive algorithms that enable a Jini system, given a fixed allocation of resources, to vary lease periods with system size to achieve the best responsiveness. We compare performance of these self-adaptive algorithms against each other, and against fixed lease periods. We find that one of the self-adaptive algorithms proves easy to implement and performs reasonably well. We anticipate that similar procedures could add self-adaptive capability to other distributed systems that rely on leases.