Mark Templeman highlights why load testing data centres should accurately emulate the loading on the electrical system, the back-up system, automatic transfer switches and the heating, ventilation and air conditioning system
The largest data centre in the world is currently underway in China and will be 6.3 million square feet when completed. That's roughly the size of 116 football pitches.
The growing popularity of cloud computing and recent regulations regarding data sovereignty are the driving forces behind the new and technically advanced data centres appearing all over the globe.
With an ever increasing investment in the safe and reliable housing of data, comes a growing need for stringent and extensive load testing of data centres.
The test phase
Traditionally, load testing of data centres comprised of testing individual systems separately, often as they're installed and the data centre infrastructure is still in a period of transition.
Furthermore, testing has focussed on the back-up generators and uninterruptable power supply (UPS) systems with little thought on testing the associated ancillary equipment.
The commissioning phase of data centre testing is crucial. Commissioning is the process that reviews and tests the data centre's physical infrastructure and design, assuring it works as one holistic system with the highest level of reliability.
Formal operations don't begin until the system is commissioned and so corners are often cut with regards to testing so as to speed up the process. Generally speaking, this is where we start to see problems.
Data centres, especially modern facilities, are highly strategic sites with advanced equipment, such as servers and HVAC units that are particularly sensitive to electrical power loss or fluctuations. This is why it’s important for load testing to be undertaken in conditions that emulate the final working environment.
The goal of load testing data centres is to balance the electrical and thermal loads. This means checking the electrical system’s functionality and the HVAC system’s performance in keeping the centre cool.
Rack load testing
Before the operational launch of a data centre, the actual capacity of the servers should be tested to ensure there is no electrical power loss. It's also essential to ensure the network performance is as expected. You don't want to get to the point of switching on and find the systems can't handle the operational capacity.
The best route to testing is to use load banks to simulate the potential future load capacity. Historically, there have been problems load testing the power and cooling systems simultaneously, so great caution should be taken at this stage.
To test accurately, specialised load banks should be installed in the data centre racks, acting as server simulators mimicking loads. These have selectable load and airflow ranges that can be set to match the electrical server load and airflow designed for each rack. This method also enables the air conditioning and cooling devices to be tested under working conditions.
Rackable load banks allow a more accurate test of where heat is generated and how it is removed from the sever room in comparison to floor standing load banks.
Rack-mounted load banks are used to complete the final stage of commissioning - the integrated systems test (IST). IST is the pinnacle of the commissioning program, because it demonstrates or dismisses the performance of the data centre as a whole against the project requirements.
The commissioned systems are operated at various loads and in different ways to demonstrate fully automated operation and appropriate response to equipment failures and utility problems.
The key to effective load testing is using the correct equipment to emulate true working conditions. Cressall's French partner, Rentaload, operates across mainland Europe hiring a variety of load banks that are suitable for data centre testing.
These can be either free standing loads for testing the ‘white space’ or 19 inch rackable load banks specially designed for accurately testing data centre systems. These load banks are designed for server room testing during building, renovation or maintenance of data centres and provide an accurate perception of functionality under normal operating conditions.
Not every company requires the data storage of businesses like Facebook, the social media giant with a 300,000 square feet data centre in Oregon, USA. Nevertheless, data centres big or small are critical pieces of infrastructure that should be properly tested during the commissioning phase; otherwise they could result in long term problems and costly downtime.
Mark Templeman is with Cressall.