Christelle Larkins, Area Manager: South Africa, MGE Office Protection Systems, says that when designing a new data centre, it is good practice to look closely at various critical components to mitigate the exposure to overloads, heat and leading power factor. In addition, users must be aware that power management becomes more critical than ever in a high density environment.
She explains that non-blade computers require components that are bulky, hot, space inefficient and duplicated across many computers that may or may not be performing at capacity. By locating these common services in one place and sharing them between the blade computers, overall utilisation is more efficient. The specifics of which functions are included and how those functions are implemented vary by blade vendor, but they share common characteristics that impact the design of today's data centres, especially in terms of power and cooling.
Although blade servers have many benefits for some applications in terms of space utilisation and potentially improved reliability, the very nature of high-density computing results in issues that must be addressed throughout planning, implementation and operation. Proper consideration of added cooling and power demands as well as changes in power delivery will ensure that users achieve the optimum levels of availability with this new architecture.
As part of the strategy to improve overall data centre reliability, most servers have moved to a dual-corded power input design to increase the “nines” of availability by eliminating single points of failure in the event of one power source or cord failing. However, this has the obvious but often-ignored consequence of lowering the load on each power supply. In transmitting only 50% of the power, efficiencies decrease, cooling and energy requirements increase and problems arise with leading load power factor.
“Most traditional UPSs were designed for 0.7 to 0.8 power factor loads and must be de-rated by as much as 30% to support a blade server load of 0.9 leading power factor,” Larkins says. “Fortunately, major UPS manufacturers have recognised these changes and responded by introducing blade server-friendly UPS systems that do not require de-rating.”
Typical issues created by blade servers include: * Higher power factor loads that result in greater Watts per VA
* High inrush current
* High heat density (3Kw to 5Kw) from one blade centre
* Higher power use in a given area due to greater density of demand
* Dynamic server demands that grow and change based on use and applications
These blade architecture considerations call for use of flexible power protection hardware that can offer the most responsiveness in a dynamic power demand environment. Traditional UPS systems must be oversized to address these issues. However, MGE Office Protection Systems' Pulsar MX UPS models have been designed specifically with blade architecture in mind. They can be installed in rack or tower configurations and offer modular designs that can accommodate changing server configurations, redundancy and backup time requirements that can provide up to 20KVA or 15KVA in redundant configurations using 5KVA sub-modules, while hot-swappable components enable maximum uptime, even during maintenance operations.
“When designing a new data centre, it is good practice for those responsible for planning and implementation to consider these factors and take adequate steps during selection and sizing of various critical components to mitigate the exposure to overloads, heat and leading power factor,” Larkins says. “It is vital that the IT team, facility management and equipment suppliers work together to create a total solution that will maximise reliability, availability and system efficiency while optimising installation and operation costs. Fortunately, solutions are available to simplify this process and enable use of blade architecture to its fullest advantage.”
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