Chapter 20 Parallel Sysplex

1. Chapter 20 Parallel Sysplex

2. 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. 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