by clicking on the page. A slider will appear, allowing you to adjust your zoom level. Return to the original size by clicking on the page again.
the page around when zoomed in by dragging it.
the zoom using the slider on the top right.
by clicking on the zoomed-in page.
by entering text in the search field and click on "In This Issue" or "All Issues" to search the current issue or the archive of back issues respectively.
by clicking on thumbnails to select pages, and then press the print button.
this publication and page.
displays a table of sections with thumbnails and descriptions.
displays thumbnails of every page in the issue. Click on a page to jump.
allows you to browse through every available issue.
GCN : November 2013
Don't let the dangerous combination of any lingering summer heat and ever-increasing processing demands leave your organization vulnerable to brownouts and other unexpected disasters. In fact, efficient, effective power and cooling can protect you in all kinds of weather --- literal or figurative. Recognize, however, that planning for dense IT equipment to support growth without aggravating or further compounding PCFE issues requires a delicate balance. Over time and successive generations of IT equipment, more gear can occupy less physical space within a cabinet, rack or blade center. But these various generations of servers also have to exist with the available primary and secondary (standby) power as well as the available cooling footprint. Minding Compute Power, Density and Ventilation Each successive generation of equipment also typically provides an increase in net processing or compute power along with a boost in memory and I/O capability. e graph shown on the following page provides an example, demonstrating that primary and secondary power constraints (until a future upgrade to the facility) will boost the per-cabinet power footprint. e relative power required per cabinet increases as the quantity of servers, their speed and the number of processing cores grow. e example makes plain that the required power per server does not scale linearly, as some improvements in energy efficiency and power management are being factored in to offset the growth. So an important takeaway is that capacity planning for servers, storage and networks needs to incorporate a facility's PCFE capabilities to address how technology improvements will help sustain growth in existing footprints. Maintaining Continuity IT data centers require electricity to operate servers, storage and networks as well as associated cooling and ventilation equipment. Energy usage may not be well understood by users, or even by most IT professionals or vendors. For a data center IT team to make effective energy allocation and configuration decisions, it will need in-depth information about energy use. Data on equipment nameplates typically provides for growth without clearly stating what energy is immediately required and what is included for growth, resulting in overconfiguration. If a data center overestimates electrical power, it will also likely overconfigure subsequent cooling capabilities, leading to excessive cooling and energy consumption. Depending on the size and importance of applications that are hosted in a data center, multiple feeds from different power sources or access points to the broader electric power grid may exist. e feed from the electric utility is considered a primary feed, with secondary or standby power provided by onsite generators. To maintain availability between a power outage and the short time before generators start up and are ready to provide stable power, uninterruptible power supply (UPS) systems are used. Power management switches enable automatic or manual transfer from primary utility or self-generated power to standby power for maintenance, diagnostics and troubleshooting, or for maintenance bypass with load balancing. Power distribution units (PDUs) transform high-voltage power supplied from energy management systems to IT equipment where it is needed. Electrical power cables can be found either under raised floors or in