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Containerized, modular data centers have emerged as an attractive solution to some enterprises that want to add computing capacity on-demand while mitigating expenses. For example, rather than building a new data center facility for disaster recovery, try deploying a container at a remote location to handle the task.
However, the promise of containerized facilities also masks potential problems. Containers usually come outfitted with servers, storage, network hardware and cooling systems; vendors say installing the container is as simple as connecting to power, chilled water and the network. But actual installations are rarely so straightforward. Before you place an order for a new data center container, it's important to understand the potentials for stress on your environment.
Consider the real estate requirements
Although containerized data centers are not buildings in the traditional sense, they occupy standard-sized 20-foot or 40-foot intermodal containers. This means each container needs to be parked in a dedicated space on the premises. The space needs to support the container's weight, remain stable in all seasons and weather conditions, and be accessible for delivery and retrieval when the unit is replaced or no longer needed.
This can pose unexpected problems in some municipalities that restrict or regulate the presence of supplemental structures. For example, if you rent or lease your place of business, you may need permission from the property owner to place the container. In addition, the local municipality may need to inspect and approve the additional structure, especially where electrical and plumbing integrity is involved. Other ordinances may apply, so it's important to confer with the building management and local government before ordering a containerized data center.
The equipment inside the container
Containerized data centers typically employ a standard rack mounting system and can accommodate a wide range of standard IT equipment. Obviously, the container's vendor would prefer to provide its own equipment, but most will support a heterogeneous mix of IT products. Regardless of the product mix, it's important to have a clear picture of the computing resources the container will support. For example, the Ice Cube IC4026HY from SGI provides 24 half-depth 60U racks and allows for two 44U roll-in full-size racks. This can be a problem is you want to use those 60U racks for full-depth servers.
Also pay close attention to the number of servers and the amount of storage that will come in the unit versus the practical life expectancy of the container. It's all about buying or leasing the "right" amount of equipment for your computing needs. For example, if predictions suggest that you'll need an additional 10,000 processing cores and 2 petabytes (PB) of storage over the next five years, it probably would not make sense to acquire a container that fits 36,000 cores and 16 PB -- you'd never use all of that excess computing capacity, so a lot of money would be wasted.
Power demands and availability
Manufacturers of containerized data centers regularly tout their excellent PUE figures, and it's easy to find a unit with a PUE of 1.2 or less. This is largely due to the pre-fabricated nature of the container where air handling and rack construction is fixed. Regardless of the energy efficiency, it's critical to consider the power demands of the container. Large, fully loaded containerized data centers can demand 1,200 kW (1.2 MW) which will invariably come from the main building's utility. This means the building must be able to supply the additional electricity to the container.
This can be a serious problem for older, smaller buildings with inadequate electrical infrastructures. Some buildings may require upgrades to the building's power distribution equipment or other changes that may involve the local utility provider. Changes or upgrades to the building's electrical system can be costly for the business in addition to the added expense of the electricity.
Also consider the impact of availability. Container-based data centers used for mission-critical workloads may need to provide a redundant electricity supply or access to the building's backup generator, which also must support the container's additional power demand. Some container vendors offer a separate generator container as a supplemental electricity source, though that is an added expense that may not have been factored into the budgeting process.
Cooling a modular data center
Some containerized data centers employ traditional mechanical cooling to handle high heat loads, but many container designs are adding air and water economizers to improve energy efficiency and reduce power costs.
When water is involved, you'll need to provide an adequate chilled water source along with a properly sized recirculation or cooling discharge facility. Vendors like SGI suggest approximately 300 tons of chiller-side cooling is needed per megawatt of power used. But the business must supply the piping, chiller, cooling tower or other water-handling equipment to feed the container's heat exchangers.
Although containerized data centers are appealing for a wide range of data center tasks, the actual acquisition of a container requires a careful consideration of the real estate, equipment, power and cooling needs of the unit. The container vendor can certainly help plan the sizing and deployment, but IT professionals should understand these requirements in advance and be able to communicate them effectively with the vendor to avoid errors and ensure a problem-free container deployment.