Dual PSU servers and UPS

[andy_nic]

I need get a new UPS, with servers with dual PSUs do you count the second redundancy one when doing the specs for a UPS? I know when it’s running it’s will only be using 1 PSU/ sharing the load between the 2. my question is when the servers boot do they draw on both full amount so my servers are 1600w each psu, when it starts would it draw 1600w between the both/one or 3200w from both.

[pantscat]

I tend to put 1 PSU into the UPS and 1 into the mains (or filtered supply) - that way if one supply fails, the other should kick in.

[3s-gtech]

1600W absolute max, as it'll work fine and boot on only one. You shouldn't spec the UPS to carry both PSUs anyway - better to have each in separate UPSs or one in a wall outlet in case the UPS fails (ask me how I know).

[DavR]

I always do 1 PSU in the mains, 1 in the UPS, too. UPS failures have hit me harder than power failures, over the years.

 

Spec on the rating of 1 PSU, but chances are, your PSU will never be drawing it's full capacity. If you have the opportunity, it would be good to run your server and observe how much power it's actually drawing - even at full pelt, my PSUs use a fraction of their rated power.

[andy_nic]

I was thinking about spitting the load would I just a surge protected pdu bar from the mains?

[3s-gtech]

A quality one, sure. Again - you want reduced risk of total failure and a poor one is more likely to be an issue than no protection on that input.

[Techie-v2]

I put 1 psu into one ups on one circuit and the other psu into a different ups powered from a different circuit from the first ups

[CrootUK]

We did split between UPS and Mains but have had way to many main spikes and even the high spec surge protector pdus didn’t protect and took the PSU out.

 

I have even found because of the load balancing some PSUs do that the difference in voltage had fed back to the UPS and caused it to get upset.

 

Dual UPS has always held us strong splitting the dual power supplies across them.

 

This is all also splitting on different circuits too.

Edited March 24, 2022 by CrootUK

[PotNoodleTech]

Dual PSU here, Dual UPS's on Dual Phases.

 

Despite each server having 2 x 1000 - 1600w PSU that is absolute max theoretical load and you'll never get anywhere near that normally.