The success of sensor-driven applications is reliant on whether a steady stream of data can be provided by the underlying system. This need, however, poses great challenges to sensor systems, mainly because the sensor nodes from which these systems are built have extremely short lifetimes. In order to extend the lifetime of the networked system beyond the lifetime of an individual sensor node, a common practice is to deploy a large array of sensor nodes and, at any time, have only a minimal set of nodes active performing duties while others stay in sleep mode to conserve energy. With this rationale, random node failures, either from active nodes or from redundant nodes, can seriously disrupt system operations. To address this need, we propose R-Sentry, which attempts to bound the service loss duration due to node failures, by coordinating the schedules among redundant nodes. Our simulation results show that compared to PEAS, a popular node scheduling algorithm, R-Sentry can provide a continuous 95% coverage through bounded recoveries from frequent node failures, while prolonging the lifetime of a sensor network by roughly 30%.