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Use Server Simulators for Integrated System Testing

Syed Ahsan Baqi

Curtail reconfiguration and retesting after commissioning by simulating high-density server operating conditions before installation. This provides an opportunity to perform the ‘Integrated System Test’, which is the pinnacle of a commissioning program. “Server simulators” are ideal for a comprehensive interface test, which involves a full load simulation using rack-mounted heaters to simulate cooling and electrical loads. The systems are operated together to ensure that the data center operates as designed in all maintenance and failure scenarios.

In ‘Level 5 Commissioning’ (Integrated System Testing), performance tests must demonstrate the correct installation and operation of each component, system, and system-to-system interface. Contractors must be able to operate each system through all modes of operation, where there is a specified system response. Verification of each sequence in the sequences of operation is required. This can be achieved by installing the load banks simulating IT equipment in the data center to fully test the power and cooling infrastructure.

The Tier Certification of Constructed Facility is intended to demonstrate that the facility can support the design. To that end, Uptime Institute monitors computer room temperatures, which are measured at different times during the facility certification. Temperature data is used to show the critical load is supported throughout the demonstrations. It’s important to ensure that the temperature difference (∆T) considered across the server simulators meets the design intent. Identifying the temperature difference and associated simulator equipment flow rates is crucial to balancing the volume of air moving through the simulator equipment with the volume of air moving through the cooling units.

Facility design engineers must not allow the server simulator manufacturers to determine the design temperature difference. These heaters must have selectable load and airflow ranges that can be set to match the electrical server load and airflow designed for each rack.

In order to cross-check temperature difference values once confirmed by the manufacturer, use hand-held temperature and humidity measuring equipment for pre-certification testing. This equipment also helps to assess the cooling efficiency by comparing the 'Server ∆T' with the 'HVAC ∆T' at the CRAC units.

Rack-mounted heaters are to be directly plugged into the same electrical distribution system installed to supply the servers; hence all distribution is also commissioned. Cooling, electrical and monitoring systems must be ready to perform when the load banks arrive and when the functional tests are set to run.

For More Information

To learn more about how IBM can help you progress on your journey to greater data center efficiency, contact your IBM representative or visit

Syed Ahsan Baqi is an experienced engineering consultant.

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