Sysplex and Coupling Facility considerations

Draft Document for Review April 7, 2004 6:15 pm

6947ch07.fm

7.1.2 Parallel Sysplex summary

Through this state-of-the-art cluster technology, the power of multiple z/OS and/or OS/390 images can be harnessed to work in concert on common workloads. The zSeries Parallel Sysplex cluster takes the commercial strengths of the z/OS or OS/390 platform to improved levels of system management, competitive price/performance, scalable growth, and continuous availability.

7.2 Sysplex and Coupling Facility considerations

Described here are the supported Parallel Sysplex configurations, required set-up information when connected to an Sysplex Timer, different forms of Coupling Facilities (CFs) supported on z990 servers, CFRM policy considerations and ICF processor assignments. The z990 models support both Central Processors (CPs) and Internal Coupling Facility (ICF) processors.

The z990 family of servers does not provide a special model for a CF-only processor. You can, however, have a z990 server with up to 16 PUs defined as ICFs.

7.2.1 Sysplex configurations and Sysplex Timer considerations

Parallel Sysplex configurations today can have system images and Coupling Facilities located across multiple servers. This can be anything from S/390 to zSeries servers. However, z990 brings some additional considerations to these types of configurations.

Message Time Ordering

As server and Coupling Facility link technologies have improved over the years, the synchronization tolerance between operating systems in a Parallel Sysplex has become more rigorous. In order to ensure that any exchange of timestamped information between operating systems in a sysplex involving the Coupling Facility observe the correct time ordering, timestamps are now included in the message-transfer protocol between the server operating systems and the Coupling Facility. This is known as Message Time Ordering.

Message Time Ordering requires a connection between the z990 CPC and the Sysplex Timer whenever a Coupling Facility is located in a logical partition on a z990.

Therefore, when a Coupling Facility is configured as an ICF on any z990 model, the Coupling Facility will require connectivity to the same 9037 Sysplex Timer that the systems in its Parallel Sysplex are using for the time synchronization. If the ICF is on the same server as one or more a member of its Parallel Sysplex, no additional Sysplex Timer connectivity is required, since the server already has connectivity to the Sysplex Timer. However, when an ICF is configured on any z990 model which does not host any systems in the same Parallel Sysplex, it is necessary to attach the z990 server to the 9037 Sysplex Timer

Even though multiple servers can connect to only one Sysplex Timer unit, the typical configuration is usually connected to two different Sysplex Timer units called an Expanded Availability configuration. Refer to IBM ^zSeries Connectivity Handbook, SG24-5444, for IBM 9037 Sysplex Timer connectivity information.

External Reference ID

A Sysplex Timer unit is assigned a unique two-digit ID at installation time, called a Unit ID. This Unit ID is referenced as an External Time Reference ID (ETR ID) in the output of the z/OS command D ETR and Support Element panels.

Chapter 7. Sysplex functions 157

990 specifications

The IBM 990 series, often referred to in the context of IBM's pioneering efforts in the realm of mainframe computing, represents a unique chapter in the history of information technology. Introduced in the late 1960s, the IBM 990 series was designed as a powerful tool for enterprise-level data processing and scientific calculations, showcasing the company's commitment to advancing computing capabilities.

One of the main features of the IBM 990 was its architecture, which was built to support a wide range of applications, from business processing to complex scientific computations. The system employed a 32-bit word length, which was advanced for its time, allowing for more flexible and efficient data handling. CPUs in the IBM 990 series supported multiple instructions per cycle, which contributed significantly to the overall efficiency and processing power of the machines.

The technology behind the IBM 990 was also notable for its use of solid-state technology. This provided a shift away from vacuum tube systems that were prevalent in earlier computing systems, enhancing the reliability and longevity of the hardware. The IBM 990 series utilized core memory, which was faster and more reliable than the magnetic drum memory systems that had been standard up to that point.

Another defining characteristic of the IBM 990 was its extensibility. Organizations could configure the machine to suit their specific needs by adding memory, storage, and peripheral devices as required. This modular approach facilitated the growth of systems alongside the technological and operational demands of the business environments they served.

In terms of software, the IBM 990 series was compatible with a variety of operating systems and programming environments, including FORTRAN and COBOL, enabling users to access a broader array of applications. This versatility was a significant advantage, making the IBM 990 an appealing choice for educational institutions, research facilities, and enterprises alike.

Moreover, the IBM 990 was engineered to support multiprocessing, which allowed multiple processes to run simultaneously, further increasing its effectiveness in tackling complex computing tasks.

In summary, the IBM 990 series represents a significant advancement in computing technology during the late 20th century. With a robust architecture, versatile configuration options, and a focus on solid-state technology, the IBM 990 facilitated substantial improvements in data processing capabilities, making it a cornerstone for many businesses and academic institutions of its time. Its impact can still be seen today in the continued evolution of mainframe computing.

IBM 990 manual Sysplex and Coupling Facility considerations, Parallel Sysplex summary

Models: 990