A sysplex is a collection of z/OS systems that cooperate, using certain hardware and software products, to process workloads. The products that make up a sysplex cooperate to provide higher availability, easier systems management, and improved growth potential over a conventional computer system of comparable processing power.

The cross system coupling facility (XCF) component of z/OS provides simplified multisystem management. XCF services allow authorized programs on one system to communicate with programs on the same system or on other systems. If a system fails, XCF services also provide the capability for batch jobs and started tasks to be restarted on another eligible system in the sysplex.

Server Time Protocol (STP) or a Sysplex Timer is required to synchronize the time-of-day (TOD) clocks for systems in a sysplex that run on different processors. Note, however, that Sysplex Timer connections are no longer supported starting with the z196/z114 servers.

In a Parallel Sysplex, central processing complexes (CPCs) are connected through channel-to-channel (CTC) communications or through a coupling facility.

A coupling facility enables parallel processing and improved data sharing for authorized programs running in the sysplex. The cross-system extended services (XES) component of MVS™ enables applications and subsystems to take advantage of the coupling facility.

A shared sysplex couple data set records status information for the sysplex.