Power Protection FEATURED ARTICLE

Stephen J. Bigelow of SearchDataCenter.com has put togethe a good list of some factors you should have in mind when looking to buy an Uninterruptible Power Source (News - Alert) (UPS), which he calls “the linchpin of the data center backup chain, providing protection against power disruptions that would interfere with workloads or even cripple server hardware.”

Bigelow boils it down to functionality and features, durability, resilience, management, monitoring, bypass control, maintenance and output as “the key components to compare” to find an UPS that fits your needs, not some other company’s needs or some vendor’s sales goal.

Resilience. It’s possible for a UPS to become a single point of failure affecting multiple servers – and if each server is virtualized and hosts multiple virtual machines, well, the carnage could be much worse. Bigelow recommends looking for a UPS that supports multiple power inputs, or to get UPS systems that support parallel operation: “Not only does this allow for greater runtime, but if other batteries in parallel fail, UPS power will still be available.”

“Particularly if you are installing a redundant UPS, step-function stability would be another important criterion to examine,” said Robert McFarlane, an analyst at Shen Milsom & Wilke, a technology consulting and design firm, cited by Bigelow. McFarlane doesn’t think it’s a good idea, however, to get an oversized UPS for “future growth,” saying that if a significant chunk of the UPS unit’s capacity isn‘t needed it’s just a waste.

Management and monitoring. “Data center UPS systems should include IP connectivity to allow remote management across an Ethernet LAN,” Bigelow said, “the same mechanism that supports remote server, storage and other systems management in the data center.”

The principle behind this is that good management tools allow you to monitor your equipment from anywhere and receive alerts if something goes wrong. The level of information and control that UPS management software allows can be a serious security flaw for careless organizations, McFarlane warns: “It should be possible to disable remote control of anything in the data center and just get operational readouts. Anything you can access and control remotely could also be accessed and controlled by a hacker or disgruntled former employee.”

Bypass control capabilities. This allows the UPS to be completely removed from the power-distribution system, which is a frequently overlooked feature, as it can prevent a defective UPS from causing a power outage that extends downtime and aids routine maintenance.

Maintenance and output. Batteries will eventually wear and fail. Field-replaceable batteries allow technicians to upgrade or replace batteries – often with no tools, so selecting a UPS with what Bigelow calls “hot-swappable batteries” means technicians can “replace old or damaged batteries without having to take the entire UPS out of service.”