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Force 10 Switches are Causing the PowerEdge M1000e Noble Fan Speeds to Rise

Article Summary: This article provides information on why Force 10 switches are causing the M1000e fan speeds to rise


Why are the Force 10™ switches causing the PowerEdge M1000e™ fan speeds to rise?


Generate a CMC Logs report.

Refer to Obtaining logs from the M1000E chassis management controller (CMC).

You would see the following in the racdump log:

# racadm getfanreqinfo
[Ambient Temperature Fan Request %]

[Server Module Fan Request Table]
<Slot#> <Server Name> <Blade Type> <Power State> <Presence> <Fan Request%>
1 LVDEDESXIP1A N/A N/A Not Present N/A
2 LVESXVDIIP1B N/A N/A Not Present N/A
3 LVESXVDIIP1C N/A N/A Not Present N/A
4 LVESXVDIIP1D N/A N/A Not Present N/A
5 LVESXVDIIP1E PowerEdge M620 Present 38
6 LVESXVDIIP1F PowerEdge M620 Present 38
7 LVESXVDIIP1G PowerEdge M620 Present 38
8 LVESXVDIIP1H PowerEdge M620 Present 38
9 LVESXVDIIP1I PowerEdge M620 Present 38
10 LVESXVDIIP1J PowerEdge M620 Present 38
11 SLOT-11 N/A N/A Not Present N/A
12 SLOT-12 N/A N/A Not Present N/A
13 LVESXVDIIP1M PowerEdge M620 Present 38
14 LVESXVDIIP1N PowerEdge M620 Present 38
15 LVESXVDIIP1O PowerEdge M620 Present 38
16 LVESXVDIIP1AP PowerEdge M620 Present 38

[Switch Module Fan Request Table]
<IO> <Name> <Type> <Presence> <Fan Request%>
Switch-1 MXL 10/40GbE 10 GbE KR Present 30
Switch-2 MXL 10/40GbE 10 GbE KR Present 83
Switch-3 MXL 10/40GbE 10 GbE KR Present 58
Switch-4 MXL 10/40GbE 10 GbE KR Present 30
Switch-5 Dell Ethernet Pass-Through Gigabit Ethernet Present 30
Switch-6 Dell Ethernet Pass-Through Gigabit Ethernet Present 30

Do not replace HW for this issue. This alone does not indicate that there is an issue.

The MXL/IOA will start requesting higher fan speed when it crosses its high temp of approximately 76C and will not stop requesting the increased fan speed until it drops below 76C and then will not start reducing fan speed until the temp drops below 60C.

IOM Health 1
Temperature <= 60C - At or below normal operating temperature.
CMC reaction Fan speed reduced 4% every 20s.

IOM Health 2
Temperature 61 … 75C - Normal operating temperature.
CMC reaction No changes to fan speed.

IOM Health 3
Temperature 76 … 83C - Elevated operating temperature, more cooling needed.
CMC reaction Fan speed increased 5% every 5s.

IOM Health 4
Temperature 84 … 85C - Critical temperature, max cooling needed.
CMC reaction Fan speed increased 20% every 5s.

IOM Health 5
Temperature >= 86C - System over temperature, thermal trip condition.
CMC reaction Fan speed at 100% PWM and IOM will shutdown after 5 s.

When MXL or IOA is inserted in the chassis, reseated, or when CMC reboots, it normally goes through a learning process to find the fan speed that provides temperature stability for the IOM. This learning process causes intended oscillations in fan speed, and the chassis may go to 80% or even 100% PWM 1 or 2 times before stabilizing. The learning process normally takes 20 - 30 minutes to complete, but in some cases it can take up to 1 hour, due to interference from Server blade requests.

Sometimes the customer has concerns that MXL / IOA installed in different chassis are stable at different fan speeds. The comparison of fan speed of different IOMs can be meaningful only under a very strict set of conditions.

To make such a comparison, the IOMs need to have the same:
  • room temperature
  • slot installed
  • number and type of external modules installed in the MXL / IOA
  • number of active internal and external links
  • number and type of fans installed
  • number and type of neighboring IOMs active
  • number and type of Server blades active
  • presence or absence of dummies in empty slots
  • traffic

All these factors affect the generation and dissipation of heat in the MXL / IOA, therefore affecting the cooling needed to achieve temperature stability.

Quick Tips content is self-published by the Dell Support Professionals who resolve issues daily. In order to achieve a speedy publication, Quick Tips may represent only partial solutions or work-arounds that are still in development or pending further proof of successfully resolving an issue. As such Quick Tips have not been reviewed, validated or approved by Dell and should be used with appropriate caution. Dell shall not be liable for any loss, including but not limited to loss of data, loss of profit or loss of revenue, which customers may incur by following any procedure or advice set out in the Quick Tips.

Identificateur de l'article : SLN286478

Date de la dernière modification : 10/03/2016 02:35 PM

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