In z/OS or S/390 environments, a technique that supports synchronous copy operations in large environments that have an expanded number of primary-storage controls and direct access storage device (DASD) volumes; this number is in excess of those supported by a single data-mover configuration. Installations can have configurations consisting of thousands of volumes in multiple extended remote copy (XRC) sessions; coordination among the sessions ensures that all volumes will be recovered to a consistent time. CXRC greatly expands upon the ability of XRC to provide remote disaster-recovery protection across a sysplex.