P-class power redundancy setting?!

[Magnus von Rosen]

Hi!

We have a bunch of old P-class enclosures that are still running and will be for another while, regrettably.

I had an issue today with the power. We have installed a second UPS in the room, with separate power sockets of course. We have moved all our C-blades to the B-power without issue after changing the C-class enclosures to "Power supply redundant" mode on the little display at the front. I know by experience that this is necessary as the default setting of "Power redundant" means that half the enclosure will go out if you loose power on one feed.
Anyway, Since I don't know much about the P-class, it predates me, I tested with an unused P-class. Half the PSU:s went out, but everything was still lit up.
Second P-class, same thing. Servers online while PS-B cable was out.
Third enclosure, POOF, no power to the right side servers! 4+2 servers out!

Since we have two more enclosures to go, which are full of very important servers, I would rather not try it again without knowing more. Obviously something is setup different from the first two and the third enclosure.

So the question finally: Is there a way to get the PSU's to work while yanking the PS-B cable? I can expect that three PSU's go out, but all servers should of course still have power from the remaining three.

I read something about a power distribution cable? Os is there a setting, like in the C-class?
I logged in to a server iLo and looked at the Rack view, but cannot find anything there to configure. Should I log in somewhere else?

Thanks in advance,
Magnus, Sweden

[gregersenj]

Hi Magnus

By default it should be A/C redundant
and it should be possible to run on 1 AC feed only.

http://h20000.www2.hp.com/bc/docs/support/SupportManual/c00172260/c00172260.pdf

It's been a long time, and the only switch I could find is the Power zone switch.
Wich is used when you got 2 3U power enclosures and 4 or 5 Blade enclosures, stacked using the scalable power bus bar.

Try to connect to the management modules, and see if there's any configuration to change.

BR
/jag

[gregersenj · Accepted solution]

Hi Again

I have just asked around.
And I was somewhat wrong.

There's to types of P-class.
There's P-Class (The old)
and Enhanced P-Class.

The Old P-Class is fully redundant: Everything is fully powered from both sides.
>Full A/C Redundant.

The enhanced P-Class:
Blades is powered on each side.
Switches is powered from both sides.
> If you loose a power feed, you loose half the servers.
You can fix that with a Bus Expander box or 2 Power enclosures and a scalable bus bar.

The Old P-Class got a physical narrow management module.
3 NIC ports and separaret ILo's.

The enhanced got a wide management module.
4 NIC ports and a shared ILo connection through the Management module.

BR
/jag

[Magnus von Rosen]

Thank you very very much! It might be that we have some old and some new enclosures, I will definitely check that out!

[gregersenj]

You're welcome.

BR
/jag

[Magnus von Rosen]

Ok, hoping for some more help.

I looked at the back of the racks.

Rack one, 40U of P-class: The old ones seem to be set up in half rack setups, with powerbars that cover one 3U PSU and two enclosures.
Those have the thinner management plastic back cover.
These had no problem loosing power on one of the feeds.

Rack two, 20U of P-class:
This is the one where power went out when I removed one feed. It is half rack setup and it has the newer wide management back side plastic cover.

Rack three, 40U of P-class:
This is the remaining one, full of extremely important servers of course.
This is a 42U setup with a very large power bar covering bottom to top.
It has the new thin management module back plastic cover. Therefore, I suppose I can expect power to go out. :)

Iv'e looked at the power zone LEDs. They all show the bottom LED lit, meaning they are all in power Zone 1.

There are 2 3U power supply in the bottom of the rack.

www.vonrosen.nu/P-klass/IMG_0325.JPG
www.vonrosen.nu/P-klass/IMG_0326.JPG
www.vonrosen.nu/P-klass/IMG_0327.JPG
www.vonrosen.nu/P-klass/IMG_0328.JPG

You mention that 2 power units and a scalable bus bar should solve the problem. Do you think that is what we have?

I can't wait to replace this with C-class...argh.

Thanks again,
Magnus

[Koopa]

Do you know if these chassis are running 3 phase or single phase? As i think they work is that single phase it shares the power along all 6 psu's and on 3 phase the first 3 psu's are powered from feed a and the psu 4,5&6 are powered from feed B, on the 3 phase if you were to drop feed b, you would lose 4 blades. Also I should think your running management module firmware 2.4 which is the latest. If so I think that power zone switch is obsalete, i Think the firmware does all that work for you now.

[Magnus von Rosen]

Hi Koopa,

they are indeed 3-phase and I recognize the behaviour you describe, it goes out by three PSUs per feed.

Is there anything besides upgrading firmware that I can try? I will certainly check that out, but that is also a risk on a customer environment, it has to be discussed and assessed and so on.

Thanks!!
/Magnus

[gregersenj]

Read page 4:

http://docs.google.com/viewer?a=v&q=cache:EwLOVPROhrEJ:hightech.lbl.gov/dc-powering/pubs/hp-blade-server.pdf+p-class+power+backplane&hl=da&pid=bl&srcid=ADGEESgnie1nl7x_Fs17s9xiS7sqYOYgUF07YPYBdnEpya2blnprXH-gFl4TUgKt4TnVkoVSxzbI0FGlDlX9DSM6pUiQnd1_qiV_FmBtekEEXIFtQwegq-QQoc0-L9EJGEGish4OGXwZ&sig=AHIEtbRNukW2dP6m19bCpI9khVZ-mt4dRA

[gregersenj]

IMG_0325 is the old man. mod.

IMG_0327 and 0328 is the enhanced module.

Yes C-Class is the way to go :)

BR
/jag