HI Lionel, Mega Ouch - I've recently seen the act of measuring power consumption in a data centre (they clamp a probe onto the cable for an AMP reading seemingly) take out a cabinet which had *redundant* power feeds - so anything is possible I guess. Regards Brian On Sat, Nov 19, 2016 at 11:20 AM, Lionel Bouton <lionel-subscription@xxxxxxxxxxx> wrote: > Le 19/11/2016 à 00:52, Brian :: a écrit : >> This is like your mother telling not to cross the road when you were 4 >> years of age but not telling you it was because you could be flattened >> by a car :) >> >> Can you expand on your answer? If you are in a DC with AB power, >> redundant UPS, dual feed from the electric company, onsite generators, >> dual PSU servers, is it still a bad idea? > > Yes it is. > > In such a datacenter where we have a Ceph cluster there was a complete > shutdown because of a design error : the probes used by the solution > responsible for starting and stopping the generators were installed > before the breakers installed on the feeds. After a blackout where > generators kicked in the breakers opened due to a surge when power was > restored. The generators were stopped because power was restored, and > the UPS systems failed 3 minutes later. Closing the breakers couldn't be > done in time (you don't approach them without being heavily protected, > putting on the suit to protect you needs more time than simply closing > the breaker). > > There's no such thing as uninterruptible power supply. > > Best regards, > > Lionel _______________________________________________ ceph-users mailing list ceph-users@xxxxxxxxxxxxxx http://lists.ceph.com/listinfo.cgi/ceph-users-ceph.com
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