What is a Parallel Sysplex?

Parallel Sysplex is a clustering technology which allows you to operate multiple copies of a z/OS as a single system image. Images can be added or removed to the cluster as needed, while applications continue to run. Operating systems participating in a Parallel Sysplex can span multiple servers and applications and data can be shared across systems. This technology can manage multiple systems and resources as a single system from a single point of control.

The benefits of Parallel Sysplex

A Parallel Sysplex is designed to achieve high scalability, performance and availability. It eliminates “single points of failure” from the hardware and operating system – as well as from the middleware and application software.


The new IBM z15, which uses this technology, is designed to deliver up to 99.99999%* availability.

The key features of Parallel Sysplex

  • Automatic Restart Manager recovers and restarts critical subsystems, either on the same system or on a different system.
  • Coupling Facility provides high-speed caching, list processing and locking.   
  • GDPS offers disaster recovery and high availability by using a cluster across two or more sites with data mirroring.
  • Generic Resource Management helps prevent a single point of failure and balances middleware workloads.  
  • Resource sharing enables physical resources such as files, tape drives, consoles and catalogs to be shared.
  • Server Time Protocol enables servers and coupling facilities to maintain common time synchronization.
  • Sysplex Failure Manager specifies a policy for failure detection intervals and recovery actions to be automatically initiated.
  • z/OS Workload Manager manages workloads via dynamic resource distribution to move workloads to systems with capacity.

Hear from customers

We’ve seen SAP application performance increase by up to a factor of two for some of our databases since migrating the underlying databases to IBM Z. We’ve had positive feedback from clients that many key applications are running faster.

Axel Herzberg, Manager System Z Infrastructure, Dataport


Use this guide for achieving near-continuous application availability.

Configuration tips

Configure your Sysplex infrastructure for high availability in Parallel Sysplex.

Best practices

Get tips on design, implementation, and management for Parallel Sysplex.

Coupling Facility (CF) options

Explore Coupling Facility technology alternatives.

CFLEVEL considerations

Learn about CPC support for coupling facility code levels.

CF structure duplexing

See how CF Duplexing provides the ultimate in resiliency for Coupling Facility resources.

IBM Z connectivity handbook

See the options available for IBM Z within the datacenter and beyond.


Learn about this multi-site application availability solution for disaster recovery.

Maximize uptime

Reduce the impact of planned or unplanned downtime.

Sizer utility

Try the CFSizer for alternate sizing techniques.

Service and support

Make the most of your IBM Z investment.

*99.99999% disclaimer: Internal data based on measurements and projections was used in calculating the expected value. IBM z15 servers must be configured in a Parallel Sysplex using z/OS 2.3 or above; GDPS management of data and middleware recovery across Metro distance systems and storage, including GDPS Metro Multi-site Workload and GDPS Continuous Availability; and DS888X with IBM HyperSwap. Necessary resiliency technology must be enabled, such as System Managed CF Structure Duplexing, Sysplex failure management and Capacity Provisioning Manager. Other configurations may provide different availability characteristics.