An enhancement to XRC called Coupled Extended Remote Copy (CXRC) allows XRC sessions to be coupled together to guarantee that all volumes are consistent to the same time across all coupled XRC sessions. With CXRC, the size of configurations XRC can handle increases. CXRC can support installations that have thousands of volumes, whereas XRC is designed to support installations that have hundreds of volumes. An enhancement to CXRC also provides the function of being able to cluster XRC coupled sessions within a single logical partition, thus allowing more XRC sessions to be coupled to a master session.