Best strategies for cooling server rooms at SMBs

By Yuval Shavit, Features Writer

Giant data centers with thousands of servers can be impressive, but for many resellers and systems integrators, the typical project is much smaller. Many small and medium-sized businesses (SMBs) have a few servers in an unspecialized room in their office, and cooling that room is different from cooling a data center built from the ground up to handle hundreds of racks. In the final installment of our Hot Spot Tutorial on server room cooling, we'll look at cooling server rooms at SMBs.

Before you start suggesting changes for your clients' server rooms, it's important to understand the SMB's technological position as well as its business constraints. Server rooms at SMBs don't have the scale of cooling problems that large data centers have, but they've still been growing rapidly, said Dan Olds, principal at Gabriel Consulting Group Inc. in Beaverton, Ore. A typical server room at an SMB may have grown from housing about 20 servers five or 10 years ago to 100 today, he said.

All that extra computing power needs to be cooled, but the good news is that blade servers -- which are very dense and thus more difficult to cool -- haven't yet become mainstream at SMBs. Most SMBs that started buying blade racks have given up on buying more, largely because of cooling costs, said Peter Sacco, president of PTS Data Center Solutions in Franklin, N.J. Those that looked to blades as a space-saving technology may have found that whatever server room space they saved with denser racks has gone to extra cooling equipment, so the net savings on floor space is negligible, he said.

Cooling server rooms at SMBs often means working with more rudimentary facilities than you would have at large data centers. Many companies don't have raised floors in their server rooms, and installing them can be very expensive. Putting in a raised floor may be altogether impossible, if, for instance, the room's roof is too low. And some server rooms are fairly disorganized, with servers and air conditioning units strewn about, Olds said, although he added that there are also many SMBs that maintain neat server rooms.

Hot Spot Tutorial: Server room cooling Learn more about server room cooling in our Hot Spot Tutorial for service providers.

On the business side, SMBs often have tighter budgets than larger companies, and some may be in a state of denial as to how bad their server rooms are from a cooling perspective, Olds said. While large companies tend to be more focused on their image and may justify renovations on the basis that they'll be seen as "going green," smaller companies may focus more on a project's ROI, he said. Overheated components fail more often and cost a business money in downtime and repairs, and overworked cooling systems are inefficient and thus increase energy costs. When you talk to a client about its server room, steer the discussion toward how fixing up the server room could save them money in the long run.

First steps for cooling server rooms at SMBs

Because your SMB client's budget probably won't allow for a custom-built raised floor, it's best to start with low-hanging fruit, Olds said. If the server room is cluttered or disorganized, tidying it up is a good first step. A neater server room will increase airflow, and it will be easier to bring in more advanced improvements.

The lack of a raised floor isn't the end of the world. Hot-cold aisles, in various configurations, can efficiently deliver cold air to servers and remove hot air. With a hot-cold aisle setup, servers are organized into rows, and the spaces between rows are alternately designated as hot- or cold-air aisles. Cold air -- which may come from in-row units or from a centralized air conditioner -- is pumped into a cold aisle, where it passes through racks and into the hot aisle on the other side. It is then collected and cooled again or pumped outside. Server rooms that use this setup sometimes put a ceiling that rests on the racks, over the cold or hot aisles, to better contain air.

Olds also recommended a special door that attaches to racks and contains a water-powered radiator. Cold water is pumped into the radiator, which then cools hot air flowing from the server as it passes through. The doors can cool air down from about 75 degrees Fahrenheit to about 65 and bring some of the advantages of liquid cooling -- specifically, the localized cooling power it provides -- without having to retrofit water blocks onto your client's servers, Olds said. This approach is cheaper than full liquid cooling but more effective than air cooling alone, so it's a good way of cooling server rooms at SMBs that have a lot of servers.

Reducing power load

Of course, the simplest alternative to cooling server rooms at SMBs is to lower the amount of heat they generate in the first place. Virtualization is a good way to consolidate servers and lower the total power your client's data center takes, and thus the total heat it produces.

Server virtualization lets your clients run several servers on the same hardware, thus reducing the number of physical servers. The goal is to reduce the number of servers that sit idle at any given moment by running several servers, none of which require full CPU utilization, on the same host system.

One of Olds' clients tested its x86 servers and found that when they ran at about 15% CPU usage, they consumed about 35% of their total power capability, he said. At 40% CPU usage, they used about 75% of their potential power draw. That means that the last 60% of a computer's CPU capability requires just an additional 25% of its maximum operating power, so two computers running at 40% utilization each will require more energy than one computer running at 80%. This means that if your client has two servers that average 40% CPU utilization each, it can save money by virtualizing them onto a similar machine, which would then run at about 80% utilization. Virtual machines can be migrated between physical servers, so your client can consolidate them during low-usage times or separate them to standby servers, which are kept off until they're needed, during peak usage.

Another option that businesses are increasingly looking at -- although not necessarily buying into yet -- is outsourcing server functions by using Software as a Service (SaaS) or having an outside provider host their websites, Olds said. This reduces the number of servers the business needs in its own server room, which reduces its cooling needs. If your business includes a managed services component, this can be a good opportunity to offer your services.

While companies are typically hesitant to trust important functionality to a third party, Olds said his usual advice about outsourcing applies: Companies should outsource non-business-critical functions that they know they can do but aren't part of their core competency. For instance, many companies would be able to host their own websites if they wanted, but find that it's cheaper to hire a hosting provider instead; e-commerce businesses may want to keep that in-house, since it's critical to their everyday operations.