What steps do typical data centers take to protect against data loss during power outages?
The [mainframe data centers] that I'm familiar with, both government and private industry, are completely protected with full blown UPS (uninterruptible power source) systems. Each site has two feeds into the UPS, each feed comes from a different power substation. Typically, the UPS transformer draws about half of the power load from each feed but will automatically switch to whichever feed stays up. If both feeds should go down, the UPS draws from twin battery banks that can last for some time. Plus the on-site generating equipment automatically starts as soon as the external feeds drop.
Normally the generators are up to speed and online supplying power within 90 to 180 seconds depending on the time it takes to synchronize the frequencies between the multiple generators. These generators are typically fueled by diesel [fuel] or natural gas. I suspect all the generators we saw running last night in New York are natural gas due to fuel storage, pollution and permit issues in big cities. At most sites the generators are started weekly and full load tests are run monthly by manually cutting the outside power feeds.
About the author:
For the past 30-plus years John Weinhoeft has had his hand in the computer industry. He recently retired from designing and managing the State of Illinois' centralized computer systems that served 100 agencies. John has authored and edited a number of analytical books published by Computer Technology Research Corporation. He is, or has been, a member of several computer organizations including the Computer Measurement Group and Central Illinois Personal Computer Users Group.