Cisco Interconnect temperature alerts

[chuckk281]

Fredy had a temperature problem:

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I could use some help in determining what is happening on 3 new C3000’s we installed yesterday.

All 3 Enclosures seem to be going in to full speed (extremely noisy) every few minutes and temperature alerts are being logged against the Cisco 9124e Switches.

If you happen to be standing in the front of the enclosure we see a very brief (3-5 seconds) cycling of the Insight Display from green to yellow, the alert gets logged and the enclosure goes to full speed. All this is reflected in the OA Syslog. This seems to be happening on only the 9124’s in bays 3-4. There are 3120’s in bays 1-2 that do not seem to have any issues. The modules feel very hot to the touch and it feels very hot at the rear of the enclosures. I vaguely remember this topic but don’t remember the fix for the issues. 

Thanks for any advice you can offer.

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from Monty:

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You only have a couple of server blades in the enclosure – and all four blades are at the bottom of the enclosure.

Is there a reason why you haven’t filled up any of the enclosures?

If you look at the c3000 Enclosure Tech Brief http://h20000.www2.hp.com/bc/docs/support/SupportManual/c01508406/c01508406.pdf page 26 you will see a picture of various supported blade and fan configurations.

The recommendation for four half-height server blades in the c3000 is to place the four servers in bays 1,2,5,6 (like your enclosure configurations), and only populate four of the six fans in bays 2, 4, 5, and 6.

The reason for this is when no servers are installed in the top device bays, the airflow doors in those bays (Figure 16, page 25) are closed and the fans behind those bays are unable to pull much air.

My recommendation is to remove the fans from bays 1 and 3 and see if the problem is corrected.  This should improve the cooling in the lower two interconnect bays, and is the tested enclosure configuration for four server blades.

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Any other suggestions or comments?