Introduction to the new mainframe zOS basics Chapter

Introduction to the new mainframe Objectives In this chapter you will learn: • How Parallel Sysplex can achieve continuous availability • Dynamic workload balancing • Single system image © Copyright IBM Corp. , 2005. All rights reserved.

Introduction to the new mainframe Sysplex Hardware Overview © Copyright IBM Corp. , 2005.

Introduction to the new mainframe 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 © Copyright IBM Corp. , 2005. All rights reserved.

Introduction to the new mainframe 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 © Copyright IBM Corp. , 2005. All rights reserved.

Introduction to the new mainframe What is parallel sysplex? (continued) • Builds on the strength of z. Series 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 nondisruptively © Copyright IBM Corp. , 2005. All rights reserved.

Introduction to the new mainframe 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 © Copyright IBM Corp. , 2005. All rights reserved.

Introduction to the new mainframe 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 © Copyright IBM Corp. , 2005. All rights reserved.

Introduction to the new mainframe 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 © Copyright IBM Corp. , 2005. All rights reserved.

Introduction to the new mainframe 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 © Copyright IBM Corp. , 2005. All rights reserved.

Introduction to the new mainframe 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 © Copyright IBM Corp. , 2005. All rights reserved.

Introduction to the new mainframe z. Series 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 © Copyright IBM Corp. , 2005. All rights reserved.

Introduction to the new mainframe 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 © Copyright IBM Corp. , 2005. All rights reserved.

Introduction to the new mainframe 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 © Copyright IBM Corp. , 2005. All rights reserved.

Introduction to the new mainframe 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 © Copyright IBM Corp. , 2005. All rights reserved.

Introduction to the new mainframe 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 © Copyright IBM Corp. , 2005. All rights reserved.

Introduction to the new mainframe Additional materials The following foils contain additional material to demonstrate points about parallel sysplex if one is not available © Copyright IBM Corp. , 2005. All rights reserved.

Introduction to the new mainframe Parallel sysplex display status Display of a 16 image sysplex Each image has reported active with the last 5 seconds © Copyright IBM Corp. , 2005. All rights reserved.

Introduction to the new mainframe 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 © Copyright IBM Corp. , 2005. All rights reserved.

Introduction to the new mainframe 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 SC 53 © Copyright IBM Corp. , 2005. All rights reserved.

Introduction to the new mainframe 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 © Copyright IBM Corp. , 2005. All rights reserved.

Introduction to the new mainframe 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 (z 900) and a 2084 (z 990) © Copyright IBM Corp. , 2005. All rights reserved.

Introduction to the new mainframe D M=CPU This shows the output from the command with the processor type, serial number and number of logical processors assigned © Copyright IBM Corp. , 2005. All rights reserved.