In IBM zSeries mainframe computers, a Parallel Sysplex is a cluster of zSeries mainframes acting together as one single Sysplex. It combines data sharing (typically using Peer to Peer Remote Copy), and parallel computing to allow a cluster of up to 32 computers to share a workload for high performance and high availability.
The forerunner of the Parallel Sysplex was the Virtual Coupling, a technique which allowed up to 12 3090 systems to execute jobs in parallel. The true Parallel Sysplex was introduced with the zSeries 900.