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PDU-UPS evolves slowly, offers partners modularity

Data center power infrastructure may not be the epicenter of IT innovation, but channel partners see vendors providing modularity, customization options and redundancy features.

Power distribution units and uninterruptible power supplies buck the typical IT industry pattern of rapid change, according to channel partners active in the data center space.

PDU-UPS technologies have long been standard components of data center power infrastructure. PDUs operate between a data center's primary power source and equipment racks housing servers and other gear. They may be mounted on the floor or in the racks. A battery-powered UPS provides temporary power when the device senses a disruption in power from the primary source. It also provides power surge protection. A PDU typically plugs into a UPS so that the downstream equipment benefits from the battery's backup power.

The PDU-UPS tandem toils in the background, mostly immune from the disruptive transformations that have roiled other facets of technology.

"It is slow changing," said Mike Parham, technology solutions architect at World Wide Technology (WWT), an IT solutions and services provider based in St. Louis. Parham, who focuses on power and cooling systems at WWT, contrasted PDU-USP technology with the pace of innovation among IT providers such as Cisco and Dell.

"It's just a different world, and it's a slower-moving world," he said of power infrastructure products.

Parham has been at WWT for eight years and worked for an equipment manufacturer before that. He said some of the UPS SKUs and part numbers that were designed during his seven-year tenure at the manufacturer are still in use today. "There are not a whole lot of IT devices that would have the same 10- to 15-year lifespan," he noted.

Less filling

That said, incremental change has come to PDU and UPS offerings. Products have shrunk in size and are more modular and flexible than in previous years.

UPS systems that use lithium-ion batteries occupy 50% to 80% less flow space than those employing lead-acid batteries, according to APC, a UPS manufacturer and a subsidiary of Schneider Electric. The newer batteries are lighter as well. Dave Wisz, executive vice president of operations at US Signal, a cloud and colocation provider based in Grand Rapids, Mich., said a smaller footprint translates into more "saleable real estate" in the service provider's data centers.

The switch to lithium-ion technology reduces the amount of maintenance required, while also reducing the carbon footprint and recycling burden. Wisz said lead-acid systems need to be replaced every five to seven years, while some lithium-ion systems have at least a 15-year lifespan.

We are seeing the focus becoming more modular and more customizable.
Mike ParhamTechnology solutions architect, World Wide Technology (WWT)

Wisz also cited scalability as a plus with today's data center power infrastructure technology. He said US Signal is deploying Vertiv's EXM multimodule UPS product line in a new data center facility being built in Van Buren Township, Michigan. Older UPS products were monolithic, while Vertiv's EXM offering can be installed in 250 kW increments. That approach lets US Signal start small and add capacity as more clients arrive.

"We don't build out from day one," Wisz said. "I don't want to go into a facility … with a huge UPS assuming they will come."

The modular systems approach "is extremely helpful to keep upfront capital costs controllable, especially where you are building a new facility," he added.

Greater customization

World Wide Technology's Parham also cited modularity as one data center power infrastructure change he has seen in recent years.

"We are seeing the focus becoming more modular and more customizable," he said. He cited the ability to scale up UPS installations incrementally in a "pay as you grow" approach.

As for customization, PDU vendors are able to provide options such as high-density outlets and specific outlet configurations. A client may want a particular arrangement of C19 and C13 outlets, for example.

"A few customers are starting to say, 'I want placement of my outlets on the PDU to be an option,'" Parham said.

Color-coding is another PDU option. This option helps in situations where a data center has A side and B side power feeds for redundancy, Parham said, noting that a customer could make A side outlets red and B side outlets blue.

Other PDU developments include static switching. A PDU with this feature is able to switch between two power sources in the event that one fails. Wisz said static switching mitigates against human error -- plugging a server into only the A side outlets. Vendors such as APC, Eaton and Vertiv provide static transfer switches.

Overhead busways

Some data center providers are taking power distribution in a different direction.

Geoff Fox, CTO at DigiPlex, a company that builds and operates data centers in the Nordic countries, said the company has phased out PDUs in the old sense of the technology. DigiPlex facilities use overhead busways, which are installed along a data center's ceiling over the equipment racks. Tap-off boxes plug into the busways, distributing power from the busways to the equipment below.

Fox said the overhead approach is much more adaptable than traditional PDUs. Tap-off boxes can be moved anywhere along the busways to accommodate customer needs.

"In terms of the flexibility of the space, and speedy deployment, it is a much better arrangement," he said.

The overhead power distribution vendor roster, once limited, has expanded.

Fox said Starline has been in the overhead busway, hot-swappable tap-off market for a while, but has been joined by other vendors such as PDI and Arnord Mardix. Overhead power distribution has been more expensive than other methods, but higher competition has brought down costs to reasonable levels, Fox said.

UPS tech faces the future

IT product and service providers expect UPS offerings to take on edge computing and provide more diagnostic data as the technology moves into the future.

IT deployments smaller than traditional data centers are emerging in organizations moving more data processing to the edge. That shift is influencing UPS product direction.

"As a matter of fact, edge requirements are already influencing UPS makers, and we are beginning to see smaller form factor UPSes emerging from folks like our partner APC/Schneider Electric, specifically to serve edge computing requirements," said Alan Conboy, Office of the CTO, Scale Computing, an Indianapolis-based hyper-convergence and edge computing vendor.

Wisz from US Signal, meanwhile, said his team is looking for advances in UPS battery health.

 "We continue to seek features that can help us predict equipment issues prior to failure, and, although it has improved over the years, UPS battery health is an area that could use some further improvement and refinement," he said. "This will help us with maintenance of the system and allow us to better forecast when we will need to budget for replacement batteries."

In addition, overhead busways let data center operators install intelligent metering devices to collect power consumption data at the point of delivery. The ability to collect accurate usage data positions DigiPlex to offer new services, according to Fox. The company, for example, is exploring the possibility of offering customers incentives to process large amounts of data during off-peak energy consumption hours. Potential beneficiaries include technology enterprises that struggle to process the vast amounts of data they collect.

"What we are … looking at for the future is linking those data processing [customers] with grid availability and making it attractive for them to process data in the middle of the night," Fox explained. Lower power costs will be the motivation for doing so.

However, metering and intelligent power distribution systems will be required to determine the best times to run heavy processing workloads, he added.

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