In IBM mainframe computers, a Systems Complex, commonly called a Sysplex, is one or more System/390 processors joined into a single unit, sharing the same Sysplex name and CDS. Put another way, a Sysplex is an instance of a computer system running on one or more physical computers. Sysplexes are often isolated to a single system, but Parallel Sysplex technology allows multiple mainframes to act as one. Sysplexes can be broken down into LPARs, or logical partitions, each running a different operating system.

Components of a Sysplex include:

• A Sysplex Timer which synchronizes all member systems' clocks
• Global Resource Serialization (GRS), which allows multiple systems to access the same resources concurrently
• Cross System Coupling Facility (XCF), which allows systems to communicate peer to peer

See also

• Parallel Sysplex
• LPAR

Mainframe computers