On Tue, September 30, 2014 1:41 pm, Digimer wrote: > On 30/09/14 02:33 PM, John R Pierce wrote: >> so I have a bunch of servers at work that are on DUAL UPS's (1 per each >> of 2 power supplies). The only thing that stopped me from doing that was: you can only use each UPS up to a half of its spec'ed current drain. Thinking in line of: having 2 UPSes for rack, how do you distribute power from them to machines which luckily have 2 power supplies each (for redundancy). Having 1 PS wired to one UPS and 2nd PS to second UPS will save you if one of UPSes failed (and does not provide any output AC). But in this case you will need UPS as powerful (current drain wise) as to power the whole rack. So you are paying for reliability by using UPSes of double capacity. Did I not miss anything? I guess I almost did: if you have 4 UPSes for 2 racks you can wire them so that if only one of 4 fails, you will have increase in draw of all UPSes only by 1/3... I decided _we_ are not that rich anyway... Its mostly HP gear, but also some Sun and IBM. >> Ideally I'd like the system to not go into shutdown unless BOTH UPS's >> that a particular box is plugged into (there's actually 4 UPS, 2 per >> each of 2 racks). Has anyone ever configured anything like that with >> NUT or whatever? Valeri ++++++++++++++++++++++++++++++++++++++++ Valeri Galtsev Sr System Administrator Department of Astronomy and Astrophysics Kavli Institute for Cosmological Physics University of Chicago Phone: 773-702-4247 ++++++++++++++++++++++++++++++++++++++++