IBM Parallel Sysplex - Sysplex

In 1990, IBM mainframe computers introduced the concept of a Systems Complex, commonly called a Sysplex, with MVS/ESA SPV4.1 in 1990. This allows authorized components in up to eight LPARs to communicate and cooperate with each other using the XCF protocol.

Components of a Sysplex include:

• A common time source to synchronize all member systems' clocks. This can involve either a Sysplex timer (Model 9037), or the Server Time Protocol (STP)
• Global Resource Serialization (GRS), which allows multiple systems to access the same resources concurrently, serializing where necessary to ensure exclusive access
• Cross System Coupling Facility (XCF), which allows systems to communicate peer-to-peer
• Couple Data Sets (CDS)

Users of a (base) Sysplex include:

• Console services – allowing one to merge multiple MCS consoles from the different members of the Sysplex, providing a single system image for Operations
• Automatic Restart Manager (ARM) – Policy to direct automatic restart of failed jobs or started tasks on the same system if it is available or on another LPAR in the Sysplex
• Sysplex Failure Manager (SFM) – Policy that specifies automated actions to take when certain failures occur such as loss of a member of a Sysplex or when reconfiguring systems
• z/OS Workload Manager (WLM) – Policy based performance management of heterogeneous workloads across one or more z/OS image
• Global Resource Serialization (GRS) - Communication – allows use of XCF links instead of dedicated channels for GRS, and Dynamic RNLs
• Tivoli OPC – Hot standby support for the controller
• RACF – Sysplex-wide RVARY and SETROPTS commands
• PDSE file sharing
• Multisystem VLFNOTE, SDUMP, SLIP, DAE
• Resource Measurement Facility (RMF) – Sysplex-wide reporting
• CICS – uses XCF to provide better performance and response time than using VTAM for transaction routing and function shipping.
• zFS – Using XCF communication to access data across multiple LPARs