1. In a redundant array of independent nodes networked together, wherein each node executes an instance of an application that provides object-based storage, a metadata management method, comprising: storing metadata objects in a set of regions distributed across the array, wherein a given region is identified by hashing a metadata object attribute and extracting a given set of bits of a resulting hash value; generating a map that, for each region, identifies a node that stores an authoritative copy of the region and thereby is responsible for receiving and responding to update requests directed to the region, and that further identifies zero or more nodes that each store a backup copy of the region and thereby are capable of acting as backup region copies to the authoritative region copy, wherein the map is generated by the following sub-steps: performing a census across at least a subset of the independent nodes networked together to determine which regions are located on which nodes currently in the array and, for each such region, a timestamp associated with a last update processed at the region; and based on the timestamps, deleting obsolete regions to generate the map; distributing the map across the array of independent nodes so that each node has an identical, global view of where the authoritative and backup region copies are located; upon receiving a request to update a given metadata object, using the map to identify the authoritative region copy for the metadata object; processing the update request; if synchronization between the authoritative region copy and at least one of its associated backup region copies cannot be maintained as the update is processed, issuing a new map so that each node continues to have an identical, global view of where the authoritative and backup region copies are located.