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

6947ch08.fm

Define the appropriate number of LCSSs (maximum is 4), based on the required number of logical partitions (maximum is 30) and the number of CHPIDs (maximum is 256 per image and per LCSS) that a future configuration may have. Spare and reserved logical partitions, which can have partition name ‘ * ‘ for future renaming as described in the previous item, can help to define additional LCSSs for future use.

Spanned channels can help to spread logical partitions across LCSSs while maintaining physical channels sharing for some channel types (see Table 3-8 on page 91 for a list of supported spanned channels).

￿Define the maximum supported number of subchannels on each LCSS.

The z990s can have up to 1890 K subchannels (63 K per logical partition * 30 partitions) total in HSA (the current maximum number of subchannels on a z900 is 63 K).

￿Configure as many Reserved Processors (CPs, IFLs, ICFs, and zAAPs) as possible.

Configuring Reserved Processors for all logical partitions before their activation enables them to be nondisruptively upgraded. The operating system running in the logical partition must have the ability to configure processors online.

￿Configure Reserved Storage to logical partitions.

Configuring Reserved Storage for all logical partitions before their activation enables them to be nondisruptively upgraded. The operating system running in the logical partition must have the ability to configure memory online. The amount of reserved storage can be above the book threshold limit (64 GB), even if no other book is already installed. The current partition storage limit is 128 GB.

￿Start with a convenient memory size.

Use a convenient entry point memory capacity to allow future concurrent memory upgrades within the same memory cards already installed on the books.

￿Use the Plan Ahead concurrent condition for I/O.

Use the Plan Ahead concurrent condition process to include in the initial configuration all the I/O cage(s) required by future I/O upgrades, allowing the planned concurrent I/O upgrades.

￿Define all possible PCI cryptographic coprocessors as candidates for all logical partitions.

You can select PCI cryptographic processor numbers in the PCI Cryptographic Candidate List of an image profile even if there are no PCIXCC or PCICA coprocessors currently installed on the server.

Considerations when installing additional books

During a z990 server upgrade, additional books can be concurrently installed. Depending on the number of additional books in the upgrade and the customer’s I/O configuration, an STI Rebalancing may be recommended for availability reasons. However the z990 STI Rebalancing, via the STI Rebalance feature, requires STI recabling and results in a server outage. It may also change ICB-4 PCHID numbers, requiring an I/O definition update.

8.7 Capacity planning considerations

The z990 servers represent a major evolution for the Series platform, extending the key platform characteristics and embracing e-business on demand requirements.

The z990 has significant performance improvements over the previous z900 servers. The z990 server includes enhanced processor and system designs, and also introduces new building blocks, such as the multi-book structure.

Chapter 8. Capacity upgrades 217

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IBM 990 manual Capacity planning considerations, Considerations when installing additional books
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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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