topic Re: Populating c7000 with 8 half-size servers in BladeSystem - General

Populating c7000 with 8 half-size servers

Sergey_k — Wed, 13 Jun 2012 14:21:31 GMT

Hello everybody,

I have a small dilemma.

We have c7000 enclosure with all 10 fans and 8 half-size servers, which are used for computations and become very hot.

What is the best way to place this servers into the enclosure to reach the best cooling?

Should I place them to bays

| 1 | 2 | - | - | - | - | 7 | 8 |
| 9 | 10| - | - | - | - | 15| 16|

| - | - | 3 | 4 | 5 | 6 | - | - |
| - | - | 11| 12| 13| 14| - | - |

or even

| 1 | 2 | 3 | 4 | - | - | - | - |
| 9 | 10| 11| 12| - | - | - | - |

or it doesn't matter

I didn't find any advises on this problem in the documentation.

PS. I think, leaving empty bays between servers is not a good idea because of poor fan redundancy in such placement variants.

Re: Populating c7000 with 8 half-size servers

Johan Guldmyr — Thu, 14 Jun 2012 05:47:38 GMT

Hello,

I don't know for sure where to put them ideally, but I think the "Technologies in the HP BladeSystem
c7000 Enclosure" page 23 can give some insight. It goes through how the cooling works in the c7000.

Link: http://h20000.www2.hp.com/bc/docs/support/SupportManual/c00816246/c00816246.pdf

Also in the appendix there are guidelines for where to install the servers.

Now as far as I can see there's no guideline for how to do when you have 10 fans and not 16 blades.

If the blades get very hot, wouldn't the best option be to place them with as much space between them as possible?

So 1,3,5,7 and 2,4,6,8 ?

Re: Populating c7000 with 8 half-size servers

Psychonaut — Thu, 14 Jun 2012 19:33:44 GMT

From what I've heard there is no "optimal" configuration. You want to make sure your slot/bay covers are in place as the system is designed to run without holes. Are the servers running hot enough that alerts/warnings are being generated?

Re: Populating c7000 with 8 half-size servers

ricdanger21 — Sat, 16 Jun 2012 21:41:14 GMT

Hi there,

Documentation states that you should populate 1-4 and 9-12.

That way you will get the most efficient setup, as you will only need 6 fans because only two zones are active. Your remaining fans will still be on, but will rotate at lower speeds.

The C7000 should support all your servers (even more, like a full 16 blade setup) at 100% load, if you ensure proper cooling (would say < 23 degree C) on your datacenter, keep all the filles in place and keep proper clearance at the front and the back.

And if you hit somehow a critical temp threshold, OA will slow down your server CPU and remaining hardware.

Regards.