6947ch07.fm

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

Restriction: The maximum distance between a pair of Sysplex Timers in an Expanded Availability configuration remains at 40 kilometers (25 miles). To achieve 100 kilometers distance between sites one option is to consider an intermediate site at less than 40 kilometers from one or the other site or to place two Sysplex Timers in one site.

Figure 7-10 on page 174 shows how a GDPS/PPRC Cross-site extended distance Parallel Sysplex can be established with RPQ 8P2263.

Site 1 100 km Site 2

 

 

 

 

 

 

 

40 km max

 

 

 

 

40 km nom

 

 

 

9037

 

 

 

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hut with

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

amplifiers

 

 

 

 

 

 

 

 

 

 

 

 

 

Route B

 

 

 

 

 

Figure 7-10 Cross-site extended distance for Parallel Sysplex and GDPS/PPRC

Note: In Figure 7-10the midspan 9037 can also be located within 40 km of site 2 or on the South path; All ETR and CLO links are provisioned as 1 channel per wavelength.

7.4.2 GDPS/XRC

XRC is a combined hardware and software asynchronous remote copy solution. The application I/O is signalled completed when the data update to the primary storage is completed. A DFSMS component, called System Data Mover (SDM), asynchronously offloads data from the primary storage subsystem’s cache and updates the secondary disk volumes in the recovery site.

The GDPS solution based on XRC, referred to as GDPS/XRC, has the attributes of a Disaster Recovery solution.

In GDPS/XRC, the production system(s) can be a single system, multiple systems sharing disk, or a base or Parallel Sysplex cluster1. GDPS/XRC provides a single, automated solution to dynamically manage storage subsystem mirroring (disk and tape) to allow a business to attain “near-transparent” disaster recovery with minimal data loss. GDPS/XRC is designed to provide the ability to perform a controlled site switch for an unplanned site outage, maintaining full data integrity across multiple volumes and storage subsystems and the ability

174IBM eServer zSeries 990 Technical Guide

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Image 188
IBM 990 manual Gdps/Xrc
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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.
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