1. Chapter 20 Parallel Sysplex

2. In this chapter you will learn:
Objectives
In this chapter you will learn:
How Parallel Sysplex can achieve continuous availability
Dynamic workload balancing
Single system image

3. Sysplex Hardware Overview

4. Sysplex Overview
A sysplex is a collection of z/OS systems that cooperate, using certain hardware and software products, to process work
Improved growth potential
Improved level of availability

5. What is a parallel sysplex?
Innovative multi-system data-sharing technology
Direct concurrent read/write access to shared data from all processing nodes
No loss of data integrity
No performance hit
Transactions and queries can be distributed for parallel execution based on available capacity and not restricted to a single node

6. What is parallel sysplex? (continued)
Builds on the strength of zSeries servers by linking up to 32 images to create the industry’s most powerful commercial processing clustered system
Every “cloned” application can run on every image
Hardware and software can be maintained non-disruptively

7. Continuous availability
Within a parallel sysplex cluster, it is possible to construct an environment with no single point of failure
Peer instances can of a failing subsystem can take over recovery responsibility for resources held by the failing instance
Alternatively the failing subsystem can be automatically restarted on still healthy systems

8. Continuous availability
In a parallel sysplex it is possible that the loss of a server may be transparent to the application and the server workload redistributed automatically with little performance degradation
Each system is still individual
Software upgrades can be rolled through one system at a time on a sensible timescale for the business

9. Capacity
The parallel sysplex can scale near linearly from 2 to 32 systems.
It can be a mix of any servers that support parallel sysplex

10. Dynamic workload balancing
The entire parallel sysplex cluster can be regarded as a single logical resource to end users and business applications
Work can be dynamically distributed to nodes with available capacity
Workload balancing also allows running of diverse applications while maintaining response times critical to the business

11. Sysplex Failure Manager Automatic Restart Manager
Ease of use
z/OS Workload Manager
Sysplex-wide workload management to one policy
Sysplex Failure Manager
Specify failure detection and recovery actions
Automatic Restart Manager
Fast recovery of critical subsystems
Cloning and symbolics
Used to replicate applications across the nodes

12. zSeries Parallel Sysplex Resource Sharing
This is not to be confused with application data sharing
This is sharing of physical system resources such as tape drives, catalogs, consoles
This exploitation is built into z/OS
Simplifies the management of the system

13. Single System Image
The sysplex should appear as a single image to operator, end user, database administrator and others
Single point of control
Persistent single image across failures

14. Applications in a Parallel Sysplex
Design goal of no application changes
Benefits
Scalability
Integration of older applications with new workloads such as web serving
With an existing sysplex there is very little infrastructure work required for a new application. The existing infrastructure may even be used without the need for a new server

15. GDPS
A geographically dispersed parallel sysplex is the ultimate disaster recovery and continuous availability solution for a multi-site enterprise
Two sites up to 100 fiber kilometers apart may be connected for synchronous updates
Asynchronous techniques may be used over this distance

16. Summary
Reduce cost compared to previous offerings of comparable function and performance
Continuous availability even during change
Dynamic addition and change
Parallel sysplex builds on the strengths of the z/OS platform to bring even greater availability serviceability and reliability

17. Additional materials
The following foils contain additional material to demonstrate points about parallel sysplex if one is not available

18. Parallel sysplex display status
Display of a 16 image sysplex
Each image has reported active with the last 5 seconds

19. D IPLINFO
This shows the first screen of response to D IPLINFO in a sysplex
Note that systems have been IPL’d at different times and are running different releases of z/OS

20. D WLM This shows the display for two of the systems in the sysplex
Note they are running the same policy activated at exactly the same time by another system SC53

21. D XCF,PATHIN
This display shows the connections to the other systems in the sysplex are by both CTC devices and via structures in the coupling facility
If the CF were to have a problem then the sysplex would continue with the CTC connections

22. D XCF,STRUCTURE
This shows a subset of the output from the command to illustrate some points
The IXC structures are the ones used by XCF, the main sysplex component
The SYSZWLM structures are used by workload manager
Note there is one structure for each physical machine
There are two machines: a 2064 (z900) and a 2084 (z990)

23. D M=CPU
This shows the output from the command with the processor type, serial number and number of logical processors assigned

24. D C This shows the console display for a system SC04 in a sysplex
Note that the only console is attached to SC47