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FOCUS COOLING


Issue 4, June 2009


WHAT ARE YOUR RESPONSIBILITIES?


Any assessment will require co-operation between the data center operator and the supplier. Reasonable requests should be adhered to, but beware of terms and conditions.


Remember, an audit will require granting the supplier access to documentation, personnel and procedures that may be commercially confidential.


On a practical level, the supplier will ask for access to telephones, copiers, faxes, conference rooms and printing facilities. You will need to consider this when looking at the costs. The supplier will want to see service level agreements with relevant suppliers.


Access to personnel, including business, IT and operational staff, will be required. It will be up to you to ensure disruption is kept to a minimum. You might consider appointing a full-time escort.


The supplier will ask for timely delivery of information. You must dictate what is reasonable and the supplier will want to ensure that its ability to deliver the service is not adversely affected. Disclosure of details of standards to which the data center operation adheres will be required.


If the audit runs into timing problems, or information is not forthcoming, the supplier will have an escalation procedure to ensure the audit is completed within the agreed timeframes. Some suppliers will want to see your organisational, configuration and process documents.


It goes without saying that the supplier will need access to the facilities and IT infrastructure. This means not just the data center, but also mechanical and electrical rooms, and any power-generation facilities that are onsite. The supplier will require a briefing on all aspects of the mechanical and electrical plant being used.


There needs to be customer personnel who are knowledgeable about the mechanical systems and electrical infrastructure, including air from outside the controlled environment (fresh air, building air, shared primary air, and so on), as well as the electrical infrastructure from the utility supply to the facility to the data center (generators, UPS, PDUs and so on).


The supplier will want to take photographs. Ensure that no proprietary information is exposed or distributed.


You will need to choose a time when no major changes are taking place to any server, storage or networking hardware or software, as this will affect the final report. Choose a quiet month.


measurements are being taken.


The data that is recorded will be used to analyse the functioning of air-conditioners, the influence of outside sources, such as exterior air temperatures, and other factors that will affect cooling.


ENVIRONMENTAL SUPPORT The setup and efficiency of the environmental support equipment that provides cooling may be evaluated in relation to site-specific conditions and hardware requirements.


Make sure that all air-conditioners serving the data center are examined, and that information regarding set points, sensitivities or dead bands, control modes, function modes, calibration, alarms and other factors are examined and documented.


The physical conditions and maintenance logs should be examined as part of the assessment.


The supplier should also wish to speak with data center management who define policies, and personnel with responsibility for maintenance of the air-conditioners. Air- conditioner and humidifier sensors should be calibrated, where possible, against a control standard, although this may be limited by the age of the equipment, or by site restrictions.


“After the assessment is complete, the supplier will work on a plan


to modify the air-conditioner and humidifier set points. The plan


will need management approval before any action is taken”


COOLING ADVICE FROM APC


Plan for a power density that is increasing and unpredictable Industry projections of power-density requirements show great uncertainty, but new data centers must meet requirements for 10 years. They must also take into account IT refreshes that occur every 18 months to two-and-a-half years. System design, so that it can be adapted easily, even retrofit, must cool high-density racks which might be isolated cases or widespread in future.


Adapt to ever-changing requirements Loads are frequently changed. It is difficult to know if the cooling system must be changed, and difficult to determine if the existing system can provide sufficient cooling. Install a cooling system where it is possible to assure that a new load can be cooled, and where cooling can be easily and quickly directed to isolated high-power loads, without complicated construction and planning.


Allow for cooling capacity to be added to an existing operating space Many existing spaces were not designed for the power density currently being installed or planned. Adding cooling capacity to an existing operating data center or network room can be difficult and costly. Retrofit options, which provide additional cooling capacity, possibly targeted at specific racks or equipment, which can easily be installed without complex planning or engineering, and without replacing or shutting down the existing systems.


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