c7000 AC redundancy (N+N)

[LuisLP]

Hi everybody,

I have a c7000 with 4 power supplies configured in an AC redundant mode (2+2),conected to two different customer power lines, and I have 8 460c baldes working in enclosure zones 1 and 2. Last week one power line turned down and the zone 2 of the enclosure turned down while zone 1 (bays 1,2,9 and 10) continued working. I don´t understand how N+N redundancy works !!! Why did blades switch off if there was a 2+2 power redundant configuration with 4 power supplies in bays 1,2, 4 and 5 ???
I have read a lot of documentation but I can´t answer the question. Please, I´ll thank you a lot any help.

[Raghuarch]

Blades shouldn't poweroff, if the N+N is Enabled with 2 power supplies.

Do you find any logs in the OA syslog? Which says server powered down Dude to ......

[LuisLP]

Thank you very much Raghuarch !!!

I´ll try access to the OA syslog to find anything but, could be the problem that enclosure power supply 1 and 4 are powered by customer power supply A, and enclosure power supply 2 and 5 are powered by customer power supply B? Must be connected power supply 1 and 2 to the same customer power supply, and the power supply 4 and 5 to the other in a N+N configuration? Is this power conecction essential or not?

Thanks a lot again for your interest.

[Phil uk · Accepted solution]

Hi Luis,
Indeed, 1 & 2 must be connected to the same supply (eg, both to Supply A), and 4 & 5 must be connected to another supply (eg, both to supply B), for N+N

Regards,
Phil

[Phil uk]

Hi,

Just found the extract from my manual:

"In N+N AC Redundant power mode, a minimum of two power supplies is required. N power supplies provide power and N provide redundancy, where N can equal 1, 2, or 3.
The Onboard Administrator reserves sufficient power so that any number of power supplies from 1 to 3 can fail, and the enclosure will continue to operate at full performance on the remaining line feed. When correctly wired with redundant AC line feeds, the AC Redundant mode ensures that an AC line feed failure will not cause the enclosure to power off.
The AC Redundant mode provides full redundancy and is the configuration requested by large enterprise customers because it ensures full performance with one power line feed."

So, if you were fully populated with PSUs for example, then 1,2,3 would go to A, and 4,5,6, would go to B
....for N+N

Phil

[LuisLP]

thank you very much !!! I´m going to reorganize power cords. For that, is it possible to change power status using OA without switching off nor the enclosure but also any blade? I thought with 4 power supplies and using OA first turn to N mode, then reorganize power cords (from power suplies 2 and 5) and at last turn again to N+N mode. Could I do it on line, without powering off blades or enclosure ??.

Thanks in advance
Best Regards,

[Phil uk]

In my honest opinion I don't know.
If by N mode you mean "no redundancy", then I suspect your enclosure may power down if you disconnect one of your power leads.

Personally, I would arrange an outage to redistribute the power cable - not easy to arrange i know.

Perhaps an ITRC expert can advise if this is possible.

Regards,
Phil

[Raghuarch]

Luis,
I thought with 4 power supplies and using OA first turn to N mode, then reorganize power cords (from power suplies 2 and 5) and at last turn again to N+N mode. Could I do it on line, without powering off blades or enclosure ?

To do it without powering off the Blade.
First set the Power mode to Not Redundant: or Power Supply Redundant: it is in Power Management page of the OA. Disable Dynamic Power. It is in the same Page.

Once your configuration is done then Switch back to AC Redundant (N+N): mode. Enable Dynamic Power.

The Enclosure uses maximum of the 3 Power supplies you can see it from the Power Subsystem page of the OA.
Since you have 8 Blades you can Do it with (N+1) or Power Redundant mode.

[LuisLP]

Thanks a lot !!!

I´ll try and I´ll tell you to close the question.

Thanks again

best regards

[LuisLP]

Thank you very much to every body. Of course I close thread... ;-)

best Regards