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The bigger thing to notice is the *lack* of noise as every server, switch and storage system spins down.<br class="">
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Keith Stokes</div>
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<div class="">On Sep 15, 2021, at 3:50 PM, Stephen Satchell <<a href="mailto:list@satchell.net" class="">list@satchell.net</a>> wrote:</div>
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<div class="">In the data centers I've worked in over the decades, those Big Red Buttons would activate a normally-closed contactor in a breaker panel. When pushed, the contactor would open, and turn off all the circults in said breaker panel. Not affected
are lights, convenience outlets, door locks, and other non-data loads. Resetting the contactor to the working position was done after throwing all the breakers to the off position, and then turn on each breaker, one at a time.<br class="">
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The only noise that I have ever heard when the Big Red Button was pushed was the loud BANG as the contactor operated. You hear a similar bang in movies in scenes where lights in a large area are turned on and off.<br class="">
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Nothing like the BANG of a 600-amp 3-phase breaker tripping -- experienced that at University of Illinois Center for Advanced Computation. You immediately look for the person holding a gun.<br class="">
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