Modularity is a powerful new concept in this industry. Unless classic reliability analysis is updated to include it, modularity’s substantial advantage to users risks misunderstanding and potentially expensive delays in acceptance. Modularizing a system can, in some cases, increase the number of internal components – for example, large UPS capacity modularized into a bank of smaller power modules will increase the number of certain electrical components and connectors.
Modularity and component count
To be valid, reliability analysis of modular systems must consider component design, function, and dependencies, and not just rely on simple multiplication of parts. Further, reliability analysis based on component count alone is incomplete – even potentially misleading – because it leaves out the new and overriding reliability advantages of modular structure, most importantly:
•Swappable modules can be removed for factory service, enabling continuous quality improvement in which defects are diagnosed at the factory and engineered out as they are discovered (this process is called “reliability growth” in systems analysis).
•Modules are manufactured in much greater quantity than a larger non-modular system, increasing even further the quality improvements already inherent in mass production.
•The generally smaller size of modules (compared to non-modular design) tends to mean less manual work during manufacture.
•Modular design allows for the considerable reliability advantage of fault tolerance – redundant modules operating in parallel, allowing for individual module failure without affecting overall system performance.
Modular components with standardized structure and connections make everything easier, faster, and cheaper – from manufacture and inventory at the vendor, through design and engineering at the planning table, to installation and operation at the customer site. Modular design is the source of one critically important component of DCPI business value (agility, the ability to respond to changing or unexpected business opportunities) and a major contributor to the other two (availability and total cost of ownership).
• Modular systems are scalable. Modular DCPI can be deployed at a level that meets current IT needs, with the ability to add more later. This ability to “rightsize” can provide a significant reduction in total cost of ownership.
Modular systems are changeable. Modular design provides great flexibility in reconfiguring DCPI to meet changing IT requirements.
• Modular systems are portable. Self-contained components, standard interfaces, and understandable structure save time and money when modular systems are installed, upgraded, reconfigured, or moved.
• Modular components are swappable. Modules that fail can be easily swapped out for upgrades or repair.
The portable and swappable nature of modular components allows work to be done at the factory, both before delivery (such as pre-wiring of power distribution units) or after (such as the repair of power modules). In-factory work has, statistically, a far lower rate of defects than work done on site – for example, factory-repaired UPS power modules are 500-2000 times less likely to cause outages, introduce new defects, or inhibit return to fully operational status compared to field-repaired modules. The ability to perform factory repair is a significant reliability advantage.2 For larger IT operations that occupy multiple facilities, modular architecture facilitates keeping as much as possible the same between installations (see earlier paragraph, One step further: standardized data centers.) Selected elements of a master DCPI design can be modified, added, or eliminated to accommodate differences in size or function between data centers without affecting other parts of the design, thereby maximizing the extent of infrastructure the data centers have in common.
Modularity enhances the effectiveness of equipment. Understandability enhances the effectiveness of people. Standardization is, by its nature, a simplifying process; a standardized system facilitates learning at every level. Increased knowledge and understanding enables people to work more efficiently and with fewer mistakes, helps them to teach others, and empowers them to participate in problem-solving. In a standardized environment, things are not only more understandable but also more predictable and repeatable, making problems less likely to occur and easier to recognize when they do. When things are easier to understand and more predictable, they are easier to explain, to document, to operate, to troubleshoot, and to fix. As these effects build upon each other, they enable staff to:
• Avoid errors. The most significant human-learning effect of standardization is reduced human error in the data center. Studies have shown that human error is the cause of 50-60% of data center downtime,3 and the potential to reduce it represents the single largest user entitlement to increased availability. Reducing human error is a classic benefit of standardization – from fewer errors in a standardized assembly process to fewer errors in diagnosing trouble in a standardized system. Standardized systems make documentation and training easier and more effective, resulting in more skilled staff that is less likely to make mistakes. Standardized controls, interfaces, and connections provide additional protection by making correct operation more self-evident. If documentation itself is standardized, error-avoidance is further enhanced by having information easily accessible in expected places and formats.
• Anticipate problems. Understanding how things work, combined with standardized procedures for such things as equipment monitoring and predictive maintenance, is a powerful defense against what might otherwise be considered “unexpected.
Share knowledge. Having structure and function “make sense” fosters ongoing learning by encouraging sharing of information – when people understand things, they are more likely to engage in conversation, collaborate on analysis and problem-solving, and learn from each other. This enhanced climate of knowledge and insight permeates everything that needs to be done with, or understood about, DCPI. • Increase productivity. As these learning effects interact and proliferate, there is an overall increase in productivity. A more knowledgeable staff means that time spent on DCPI-related matters is used more efficiently. With equipment and procedures easier to understand, less time is spent training and being trained. With reduced human error, less time is spent recovering from human-caused problems and less help desk time is spent responding to calls related to such problems. All these economies of time free up human resources for the functional business of the data center – the work of the IT equipment that is powered, cooled, and protected by DCPI – rather than for management of the DCPI layer itself.
The standardization of components enables dramatic economies in the production, delivery, and servicing of goods. The most well-known of these is the ability to mass produce a product. How standardization drives DCPI business value > Benefits of mass production
•Lower cost
•Higher quality
•Easier servicing
•More product capabilities
•Faster delivery
Standardization of parts and processes is what enables mass production Although the idea has been around since the 1100’s, when the Venice Arsenal in Italy produced nearly a ship a day using assembly lines and mass produced parts, it was reintroduced in the Industrial Age by Henry Ford’s famous moving assembly lines and task-oriented workers.
One type of human error that is reduced before the user even sees the product is humancaused manufacturing defects. Standardized modular design maximizes the opportunity to mass produce, which drives out human error in the manufacturing process by the repeatable nature of standardized assembly and by the increased ability to recognize and eliminate defects in such a process. As shown in the previous section, modular structure and increased human learning – two fundamental and empowering characteristics of standardized DCPI – provide a wide range of direct and commonsense benefits. This section will look at standardization more closely, and from a different viewpoint – a bottom-line viewpoint – to demonstrate, point by point, the value of standardization to the enterprise. Modularity and increased human learning spawn benefits in three critical areas of performance which, taken together, constitute the business value of DCPI.
Things that increase availability or agility and things that decrease total cost of ownership are drivers of DCPI business value. In a remarkable network of causes and effects, standardization creates benefits that simultaneously drive all three of these “performance vectors.”
How standardization increases AVAILABILITY The major factors affecting availability (Figure 4) are:
• Reliability of equipment – Increased equipment reliability means reduced risk of downtime.
• Mean time to recover (MTTR) – Faster recovery after failure means less downtime.
