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N4000 power supply question (Info only question)

 
Chris H_3
Advisor

N4000 power supply question (Info only question)

Hi all,

We just got an N4000 class system and it has 3 power supplies, and it wouldn't fire up without power to all 3. I was just wondering, does it just need to have them all plugged in because it wants to have redundant, or are all being used? I'm assuming one is the backup.

I tried navigating HP's site to look for this info but, to me, that site blows. Or, maybe I don't know how to properly access the info on it :)

Thanks
CH
3 REPLIES 3
Keith Bryson
Honored Contributor

Re: N4000 power supply question (Info only question)

Hi there

An HP engineer once told me that you need ALL PSUs available to power-up and boot the system. During OS operation, one PSU can fail without interrupting normal operation.

Hope that helps - Keith
Arse-cover at all costs
Stefan Stechemesser
Honored Contributor

Re: N4000 power supply question (Info only question)

Hi CH (?),

the N-Class can boot with only 2 power supplies, but ana warning message will be logged at bootup and the bootup will be delayed by 30 sec unless you acknowlege the warining at the console.
Another reason could be that one of the still plugged in powersupplies is out of order.
You can check this with the "ps" command on the GSP.
The 3rd powersupply is for n+1 redundancy only, but all three powersupplies are used via load balancing.
By the way, the base version that HP sold included only 2 power supplies. The 3rd was optional.

best regards

Stefan
timmy b.
Honored Contributor

Re: N4000 power supply question (Info only question)

Chris, it sounds to me like you're only running on two power supplies, even though you have "good" power on all three power cords. (Are you sure you even have three power supplies?)

To check the status of your power supplies, remove the front panel and look through the EMI shield. The power supplies take up the bottom half of the front of the server; left, center and right. There should be a green light visible on each of the power supplies. If one light is not on, check the TINY little black ENABLE switch next to the light. If the switch is ENABLED but the light unlit, you either don't have a good power cord to it or the power supply is defective.

See page 148 of this document. http://docs.hp.com/en/3687/rp7400_customer_hardwaremanual.pdf

Good Luck.
There are 10 kinds of people in this world: Those who understand Binary, and those who don't.