What is a Parallel Sysplex?

A Parallel Sysplex is a clustering technology that allows the customer to operate multiple copies of the mainframe operating system as a single system. This configuration is analogous in concept to a UNIX cluster, but allows systems to be added or removed as needed, while applications continue to run. This flexibility enables mainframe customers to introduce new applications or discontinue use of applications in response to changes in business activity.

Extend the strengths of the mainframe

  • Reduce your overall cost of computing
  • Provide rapid, flexible responses as your business needs change
  • Ensure the continuous availability of your IT assets
  • Leverage your past IT investments – no application changes required

The Parallel Sysplex system gives us scalability and cost savings while adding to our ability to maintain service levels.

Cassie Smith, Technical Manager Software Services, Absa Bank,


System management 

Parallel Sysplex allows users across multiple systems to access the same databases concurrently, with database access controlled at the record level.

Manage multiple images as a single image: Innovative multisystem data sharing technology allows you to link up to 32 z/OS systems as a single, highly-scalable, highly-available logical computing facility, while the underlying structure of the Parallel Sysplex remains virtually transparent to users, networks, applications, and even operations.

Concurrent read/write access: The z/OS Parallel Sysplex enables direct, concurrent read/write data access to shared data from all processing nodes in the configuration without sacrificing performance or data integrity.

Scale nearly linearly from 2 to 32 systems: Use a mix of any servers that support the Parallel Sysplex environment.

Clone configurations across servers: Grow from a single to multiple servers in a Parallel Sysplex without having to grow the operations and support staff.  System symbolics allow a definition change to be made once and get reflected on multiple instances, or an operator to issue a single command that can go to one or multiple LPARs.

99.999% end user availability
All systems in the Parallel Sysplex can have concurrent access to all critical applications and data, so that application availability remains intact. Work flows to the system with the most capacity provide the user with the best response times.

Featured technology
GDPS®  is a multi-site or single-site end to end application solution that allows remote copy configuration and storage subsystems to automate Parallel Sysplex operation tasks and perform failure recovery from a single point.

No single points of failure: In the event of failure in the Parallel Sysplex environment, the OLTP workload is automatically and quickly redistributed. Automatic Restart Manager enables fast recovery of the subsystems that might hold critical resources at the time of failure.

Workload distribution: In the event of failure in the Parallel Sysplex environment, the OLTP workload is automatically redistributed without operator intervention.

Update without disruption: The nodes in a cluster present a single image but remain individual systems, so that you can introduce changes such as upgrades one at a time while remaining systems continue to process work.

Dynamic workload balancing: New work requests flow to the systems that are available, with end-user availability maintained at the network level (with z/OS Workload Manager, Virtual IP Addressing takeover capabilities, Sysplex Distributor, or VTAM Generic Resources) and at the transaction level (with CP/SM, IMS Shared Message Queues, or WebSphere MQ Shared Queues).

99.5% scalability
Parallel Sysplex allows up to 32 LPARs on up to 32 servers to run the same application in data sharing mode, each with direct read/write access to the data.

Grow your data center without expanding operations and support staff

“At US Bank we look to expand through acquisitions. With our Parallel Sysplex environment, we know that we can quickly add processing power and grow databases while still maintaining consistent service levels even if we more than double the size of the business.”  – Mark Sobotka, VP Technical Services, US Bancorp

Additional management features

Generic Resource Management

Provides the ability to specify to VTAM a common network interface. This can be used for CICS TORs, IMS TM, TSO, or DB2 DDF work. For example, if one of the CICS TORs fails, only a subset of the network will be affected. The affected terminals will be able to immediately logon again and continue processing after being connected to a different TOR.

Automatic Restart Manager

Quickly recover subsystems that might hold critical resources at the time of failure. The Automatic Restart Manager (ARM) reduces operator error by detecting the failure of a critical job or started task, automatic restart after failure and automatic redistribution of work to an appropriate system following a system failure.

Sysplex Failure Manager

Allows the installation to specify failure detection intervals and recovery actions to be automatically initiated in the event of the failure of a system in the Sysplex.

z/OS Workload Manager

Provides Sysplex-wide workload management capabilities through dynamic resource distribution, based on installation-specified performance goals and the business importance of the workloads.

Resource Sharing

Enables sharing of physical resources such as files, tape drives, consoles, catalogs, etc. with significant improvements in cost, performance and simplified systems management.  

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