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p-Class Blade Power Question

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Occasional Contributor

p-Class Blade Power Question


We have a p-Class HP Blade Rack: with three 8 slot Standard Blade Enclosures and two single phase 3U power enclosures (G1) (each with four power supplies) and scalable bus bars. The enclosures are populated with 16 BL20p G2, 6 BL20p G3 and 2 BL25p.

According to the HP Blade power calculator spreadsheet we have sufficient power.

All status lights are green - on power supplies, bus bars, enclosures, management modules, etc.

HP Insight manager shows no faults and says power usage is less than the maximum. For example an average power supply reports:

Current: 7.632 A
Max. Current: 57.0 A
Power: 392 W
Max. Power: 2929 W

The power enclosures are firmware 2.30 and the individual power supplies are firmware 1.70.

Basically everything (to my limited understandaing) is saying it is fine.

The problem is out of all the blades we have two that will not power up. Or to be precise we have two slots that will not power up.

Slot-7 in two of the three enclosures will not power up any blade (slot-7 in the third enclosure works perfectly). No matter what blade we put into the slot7 just refuses to power up - the only thing that comes on is the red error light on the blade. The servers work perfectly elsewhere, if we connect via the front iLO port we can "force" the blades to power up using the "override" option. I'm not happy about doing that, partly because the server will not power up again if we switch it off.

Looking in the IML on another blade and we can see the error "Power Enclosure Power Supplies Not Redundant (in Enclosure, Enclosure Address 1CAF)". In my naivety I would have expected some sort of red/amber error light somewhere.

Occassionally we see the error "Server Blade Enclosure Rack Name Conflict (Enclosure Serial Number .............)". Checking the names (against the serial numbers) and we can see no duplicates or conflicts. The serial number mentioned (and not shown) is one of the power supply enclosures, but they all have unique names.

We have tried removing some of the blades, and giving it enough time to notice the change in power requirements. Reducing the power load in this manner makes no difference, and we still cannot power up the blades in the slot 7s.

Any advice, or pointers would be gratefully received.


Honored Contributor

Re: p-Class Blade Power Question

If the problem is limited to one particular slot I would guess the enclosure backplane is faulty - I do not think it could be caused by any power limitations.

Don't panic! [THGTTG]
Wesley Staal

Re: p-Class Blade Power Question


We had the same problem where bl25p's did not boot, but bl20p's did boot. HP had the enclosure backplane replaced which solved the problem..
Navaneeda Kumar
Frequent Advisor

Re: p-Class Blade Power Question


Chnage the Blade Enclosure Back Plane. This will resolve the issue.

Also before changing you can just press the reset button in the Enclosure Back Plane and try,

Thomas J. Harrold
Trusted Contributor

Re: p-Class Blade Power Question

Seems odd that two of your 3 enclosures would have a backplane problem. In any case, I'd log a support call, as blade power is a bit complex.
I learn something new everyday. (usually because I break something new everyday)
Oleg Koroz
Honored Contributor

Re: p-Class Blade Power Question

If you can force from ILO server to working fine:
Would be possibly for you to turn off breakers from scalable bar to both suspected enclosures and swap management module from good known enclosure. Than turn on Barkers apply power and test one Enclosure at time with swapped management module? You can swap it on the fly as it Hot Plug module. If you turn off barkers it might switch problem to different bay.
If going to request Backplane - you need to know which one Power or Signaling?
Oleg Koroz
Honored Contributor

Re: p-Class Blade Power Question

forgot to mention if ilo wil power System fine - you might need only management module replacement
David Child_1
Honored Contributor

Re: p-Class Blade Power Question


I know this is a bit late and something I'm sure you have probably already checked, but its better to be safe;

Ensure the "Automatically Power on Server" option is set to "Yes" on the iLO Virtual Devices -> Virtual Power page.

I've had to replace the management module due to a slot not powering up, but in that particular case I was not able to power up the blade via the iLO.

chris barnett_2
Frequent Advisor

Re: p-Class Blade Power Question

Is the power enclosure load balancing cable installed. There is a little white socket on the left hand side of each power enclosure. There should be a link cable between the two power enclosures, this allows the blades to pull power from least loaded enclosure. It may also explain the non redundant message as the two power enclosures are not aware of each other.
Occasional Visitor

Re: p-Class Blade Power Question

I not sure how much this helps, but you might want to make sure that your firmware versions are the same for both the blade enclosure and the power enclosure. We had similar issues with a bunch of our blades and this cleared up some of the these issues.