Replicated instances in a database environment provide for automatic failover and recovery. A monitoring component can obtain a lease enabling the component to periodically communicate with, and monitor, one or more data instances in the data environment, where the data instance can be a replicated instance including a primary and a secondary replica. For a large number of instances, the data environment can be partitioned such that each monitoring component can be assigned a partition of the workload. In the event of a failure of a monitoring component, the instances can be repartitioned and the remaining monitoring components can be assigned to the new partitions to substantially evenly distribute the workload.