ProLiant Servers (ML,DL,SL)
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Redundant power supply question

Occasional Advisor

Redundant power supply question

Hi --


I'm having some trouble understanding how the server will behave with two power supplies.

Let's say I have power supply #1 connected to circuit A, and power supply #2 connected to a UPS which is connected to circuit B.


Circuit B fails. What will the server do?


I know what I would like it to do, but I don't t think that's what would happen ...




Honored Contributor

Re: Redundant power supply question



The server will continue running on both powersupplies until the UPS runs out of power. Then it will run everything on one powersupply and the HP Agents will alert you that one powersupply has failed.

Occasional Advisor

Re: Redundant power supply question

Looking in to this I also have a question as to how the power is drawn. We have 4 Proliant Servers with Redundant PSU. These are connected to 2 UPS systems and we are trying to properly distribute power among these 2 for proper runtime during a powerfailure. Is there a Primary PSU and a Secondary or does the switching unit draw power evenly from both PSUs?

Re: Redundant power supply question

There is NOT a "Primary" and "Secondary".  As long as the total server current load can be supplied by *one* of the power supplies, server power is considered redundant.  Regardless of which one fails the other will pick up the slack until the bad one is replaced.