The following topics are discussed in this chapter:

To plan the journey ahead, you must understand the available options and where you stand today. It also helps to know some of the history.

Power is performance redefined. Everyone knows what performance meant for IT in the past: processing power and benchmarks. Enterprise Systems, entry systems and Expert Integrated Systems built on the foundation of a POWER processor continue to excel and extend industry leadership in these traditional benchmarks of performance.

Let us briefly reflect on where we are today and how we arrived here.

Over the years, the IBM Power Systems family has grown, matured, been innovated and pushed the boundaries of what clients expect and demand from the harmony of hardware and software.

With the advent of the POWER4 processor in 2001, IBM introduced logical partitions (LPARs) outside of their mainframe family to another audience. What was seen as radical then, has grown into the expected today. The term virtualization is now common-place across most platforms and operating systems. However, what options a given platform or hypervisor provides greatly varies. Many hypervisors provide a number of options to achieve the same end result. The availability of such options provides choices to fulfill the majority of client requirements. For general workloads the difference between the various implementations may not be obvious or apparent. However, for the more demanding workloads or when clients are looking to achieve virtualization or utilization goals, the different approaches need to be understood.

As an example, PowerVM can virtualize storage to an LPAR through a number of routes. Each option delivers the required storage, but the choice is dictated by the expectations for that storage. Previously the requirement was simply for storage, but today the requirement could also include management, functionality, resilience, or quality of service.

We cannot stress enough the importance of understanding your requirements and your workload requirements. These complimentary factors provide you, the consumer, with enough knowledge to qualify what you require and expect from your environment. If you are not familiar with the range of options and technologies, then that is where your IBM sales advisor can help.

POWER processor-based servers can be found in three product families: IBM Power Systems servers, IBM Blade servers and IBM PureSystems™. Each of these three families is positioned for different types of client requirements and expectations.

In this book we concentrate on the Power Systems family. This is the current incarnation of the previous System p, pSeries and RS/6000® families. It is the traditional Power platform for which clients demand performance, availability, resilience, and security, combined with a broad, differentiated catalogue of capabilities to suit requirements from the entry level to the enterprise. As an example, Table 1-1 on page 3 summarizes the processor sizings available across the range.

The smallest configuration for a Power 710 is currently a single 4-core processor with 4 GB of RAM. There are configuration options and combinations from this model up to a Power 795 with 256 cores with 16 TB of RAM. While Table 1-1 may suggest similarities between certain models, we illustrate later in 2.3, “Performance consequences for I/O mapping and adapter placement” on page 26 some of the differences between models.

IBM Power Systems servers are not just processors and memory. The vitality of the platform comes from its virtualization component, that is, PowerVM, which provides a secure, scalable virtualization environment for AIX, IBM i and Linux applications. In addition to hardware virtualization for processor, RAM, network, and storage, PowerVM also delivers a broad range of features for availability, management, and administration.

For a complete overview of the PowerVM component, refer to IBM PowerVM Getting Started Guide, REDP-4815.

The chapters in our book are purposely ordered. Chapters 2, 3 and 4 discuss the three foundational layers on which every Power Systems server is implemented:

Configuration and implementation in one layer impacts and influences the subsequent layers. It is important to understand the dependencies and relationships between layers to appreciate the implications of decisions.

In these four initial chapters, the subtopics are grouped and ordered for consistency in the following sequence:

The first four chapters are followed by a fifth that describes how to investigate and analyze given components when you think you may have a problem, or just want to verify that everything is normal. Databases grow, quantities of users increase, networks become saturated. Like cars, systems need regular checkups to ensure everything is running as expected. So where applicable we highlight cases where it is good practice to regularly check a given component.

The word performance was previously used to simply describe and quantify. It is the fastest or the best; the most advanced; in some cases the biggest and typically most expensive.

However, today’s IT landscape brings new viewpoints and perspectives to familiar concepts. Over the years performance has acquired additional and in some cases opposing attributes.

Today quantifying performance relates to more than just throughput. To illustrate the point, consider the decision-making process when buying a motor vehicle. Depending on your requirements, one or more of the following may be important to you:

These three fall into the traditional ideals of what performance is. Now consider the following additional attributes:

All are elements that would help qualify how a given vehicle would perform, for a given requirement.

For example, race car drivers would absolutely be interested in the first three attributes. However, safety features would also be high on their requirements. Even then, depending on the type of race, the wheel clearance could also be of key interest.

Whereas a family with two children is more likely to be more interested in safety, storage, seats and fuel economy, whereas speed of acceleration would be less of a concern.

Turning the focus back to performance in the IT context and drawing a parallel to the car analogy, traditionally one or more of the following may have been considered important:

Whereas today’s perspective could include these additional considerations:

Do you need performance to be fastest or just fast enough? Consider, for example, any health, military or industry-related applications. Planes need to land safety, heartbeats need to be accurately monitored, and everyone needs electricity. In those cases, applications cannot underperform.

If leveraging virtualization to achieve server consolidation is your goal, are you wanting performance in efficiency? Perhaps you need your server to perform with regard to its power and physical footprint? For some clients, resilience and availability may be more of a performance metric than traditional data rates.

Throughout this book we stress the importance of understanding your requirements and your workload.