– Robert Neave is a Co-founder and Vice President of Sustainable IT Initiatives at nlyte Software (www.nlyte.com)

Why are we hearing more about raised floors not being used in the
data center?
There has always been an issue with the fixed size of the plenum (raised floors space) within datacenters and its usage. The plenum is traditionally used to push the cooled air to devices and for the placement of datacenter services such as network and power cables. These two contradicting usages of the same space place an increasing strain on the datacenters ability to function efficiently. Rarely are data centers built from the ground up as data centers. In many cases data centers are just repurposed rooms. Depending on the room, it can be less expensive to implement overhead cooling and cable management than installing a raised floor. We suspect that cost is why we are hearing about more data centers being constructed without raised floors.

Can you save costs?
Yes & No, some designers will argue that by removing the plenum you limit the expense of heavy plant to cool the datacenter and the costs of under floor maintenance, while other designers will argue that you have just moved the maintenance pains and cost to above the floor or rack.

Can you run cables easily?
Companies that have designed their data center without a plenum are using above cabinet cooling units and ceiling-mounted cable trays to address the issue of not having a raised floor. In some cases, we see these
ceiling-mounted strategies used in data centers that also have raised floors to increase capacity. In these centers out of capacity, adding additional cooling units and cable trays above the floor can be the easiest and least expensive solution to their problem. When considering the physical labor required to pull cable in the data center, the raised floor is a better choice because it eliminates the need for multiple people on ladders to get the job done.

Advantages and Disadvantages?
There are advantages and disadvantages to both approaches. For example, very few data centers rooms we built from the ground up to support data center equipment, they are standard rooms that have been repurposed for data center support. If these rooms have high ceilings, it can be very expensive to get the overhead cooling close enough to the tops of the cabinets to effectively cool the equipment. In these cases, a raised floor approach might be the better choice.

Raised floor can be a very expensive proposition in large data centers. There are people that claim that raised
flooring creates a security issue for entering a data center undetected. In many cases, when data centers are reconfigured, the existing cabling is left in place because it is cheaper to leave it than to pull it out. Over time,
this practice can interfere with the air flow under the floor and reduce the cooling capacity of the data center.

What do you recommend if an IT manager is planning a data center renovation or move soon?
A complete model of the datacenter and an inventory of the all affected equipment captured within an affective DCIM tool; “you can model changes athousand times within a DCIM tool, but you can only want to layout a data center once”.

When considering a DCIM solution to help you decide which approach is best for your company, (raised floor or above cabinet cooling and cabling), you need to choose one that uses a real-world approach to visualizing your data center assets. Most of the DCIM solutions in the marketplace do a great job mapping the data center floor, but only GDCM’s nlyte models the data center as a cube. With nlyte, assets under the floor, on the walls, and above the cabinets are visually modeled in their exact location, providing better management and planning regardless of your strategy for cooling and cable management.