topic Re: Dual Power Supply in ProLiant Servers (ML,DL,SL)

Dual Power Supply

Dave Norwood — Sat, 20 Aug 2005 19:53:32 GMT

I have been told that if you have dual power supplies in a Proliant server (RPS), you should put them both on one power circuit. This is because two circuits could proved different power levels which would be hard on the server. Of course, I have also heard you should put each power supply on a different circuit for redundancy/fault-tolerance. Which is correct?

Thank you!

Re: Dual Power Supply

Oleg Koroz — Sat, 20 Aug 2005 20:55:07 GMT

Not mandatory to make assumption ..hard on the serverâ ¦
Probably you don't expect at one Circuit 108V and at Second 135v (or 210v and 240v).
If there will be any Power Spikes - worst what can happen, power Supply will fail or other components. Split between two circuits makes sense in case if one circuit gets failure (either from wall outlet or from UPS where second circuit will continue Provide Power to Redundant Power Supply. If you use redundant Power Supply a small difference on the input won't produce any problem, from Power Management tool you can see load and Input Voltage on the each power Supply. If Voltage exceed any limit Agent will generate log and alert to monitoring tools.

Re: Dual Power Supply

Steven Clementi — Sat, 20 Aug 2005 23:19:18 GMT

Dave:

You wouldn't be from the Delaware Norwood's would you?

Potentially, you could have different voltages on 2 seperate curcuits and that would not be the best situation.

The truth is, for most proper situations, that the provided seperate circuits usually run through a UPS which has regulated the voltage and both circuits supply the same level of server. You obviously should NOT connect 1 power supply to Low Voltage (108-135v) and 1 power to High voltage (200-240v), but for best redundancy... you should connect the 2 to seperate UPS's or circuits feed from different supplies (but at the same voltage level).

In other words, you should always try to plug each power supply into 2 different power circuits wherever possible, just as long as they are the same Power/Voltage level.

Steven

Re: Dual Power Supply

Mahesh Kumar Malik — Sun, 21 Aug 2005 07:12:34 GMT

Hi Dave

Recommendation is to connect two power supplies to different circuits so that in the event of failure of one circuit, another supply can continue to power the system.

Regards
Mahesh

Re: Dual Power Supply

Dave Norwood — Sun, 21 Aug 2005 14:09:52 GMT

Thank you all for your responses. I did understand that both circuits should be the same rated voltage, but you can get slight variances between two circuits that are rated the same.

In any event, everyone seems to agree that putting the two power supplies on separate UPS/circuits is the best situation.

BTW: I am related to the "Pennsylvania Norwoods", but I don't know of any relatives in Delaware.

Thanks again.

Re: Dual Power Supply

Dave Norwood — Sun, 21 Aug 2005 14:13:12 GMT

Closing thread, thank you to everyone. Consensus is I put the two power supplies on separate circuits.