An archival storage cluster of symmetric nodes includes a metadata management system that organizes metadata objects. Each metadata object may have a unique name, and metadata objects are organized into regions. A region is selected by hashing one or more object attributes and extracting a given number of bits of the resulting hash value. The number of bits may be controlled by a configuration parameter. Each region is stored redundantly. A region comprises a set of region copies. In particular, there is one authoritative copy of the region, and zero or more backup copies. The number of backup copies may be controlled by a configuration parameter. Region copies are distributed across the nodes of the cluster to balance the number of authoritative region copies per node, and the number of total region copies per node. Backup region copies are maintained synchronized to their associated authoritative region copy.