Critical Systems Testing, Inc., (CST) performed mechanical and electrical testing on the eBay Denver data center in Englewood, CO. in 2004.
This critical data center, in addition to housing primary servers serving the internet auction functions, was the principle location for the newly acquired pay pal financial servers. The facility was remodeled for eBay, originally designed for another, now defunct, internet services provider that never occupied the facility. The scripting and implementation of the testing procedures provided a set of interesting challenges that revealed unexpected limitations and critical design flaws.
The mechanical systems serving the data floor were comprised of 30 ton split DX Liebert computer room air conditioning (CRAC) units, with pad mounted condensing units in a secure yard. Our original functional tests and subsequent capacitance tests with load banks revealed that the refrigerant charges in the CRAC units were low. Even after additional refrigerant was added, the tested cooling capacity of the CRAC units was well below the engineers design. This fact alone was significant in that it limited the number of servers that this facility could host.
The Integrated Systems Test, which was subsequently performed after the individual equipment and system functional tests, revealed an unexpected flaw in the site design. It was discovered that, during the simulated utility loss test under full electrical load, multiple CRAC unit failures were experienced. Further investigation revealed that when the emergency power generators started, heat plumes created by the discharge air from the cooling systems were causing the CRAC units to fail on high head pressure. This resulting loss of cooling capacity, had it not been found, would have caused catastrophic failures during a utility loss event.
This scenario highlights the critical need for Integrated Systems Testing utilizing load banks on the data floor to simulate a fully occupied and operational data center prior to occupancy. Problems and potential failures may remain undetected, like ticking time bombs, if not fully tested under load during all types of failure scenarios. Increased reliability, enhanced performance and reduced operational expenses is the mission of Critical Systems Testing, Inc.