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7910 missing fan error message.

 
mekand
Occasional Advisor

7910 missing fan error message.

Hello,

I installed only one switching fabric module for the HPE 7910 switch and installed it in the lower switching fabric module slot as illustrated into installation guide. I also installed a fan tray in the lower fan tray slot.

Now, I receive these messages at console...

%Apr 14 16:31:01:854 2016 ME-CORE DEV/3/FAN_ABSENT: -MDC=1; Chassis 1 fan 1 is absent.

%Apr 14 16:31:24:100 2016 ME-CORE DEV/3/FAN_ABSENT: -MDC=1-Chassis=2-Slot=11; Chassis 2 fan 1 is absent.

Why?

Thanks.

Regards.

Andrea

15 REPLIES
pattap
Regular Advisor

Re: 7910 missing fan error message.

are they additional fans or they've been installed on tha same chassis previously and you just moved them to different slots?

mekand
Occasional Advisor

Re: 7910 missing fan error message.

Good questions.

7910 is configured with one fabric module and one fan tray.

I don't know if fan moved from a slot to another.

Regards.

VoIP-Buddy
HPE Pro

Re: 7910 missing fan error message.

The fan tray is an integral part of the switching fabric tray.  You need a second fabric tray and slide the fan tray into that.  That said, you should be able to run the 7910 with one fabric and fan tray.  Ignore the messages.

If you take out the second fan tray, make sure that you replace the blank panel to cover the hole or you will have heat issues.

David

sdide
Respected Contributor

Re: 7910 missing fan error message.

Hi,

I've had the exact same issue.

I'm not sure if the 7910 is supposed to ONLY run with 2 (MPUs and fans) in normal operation and therefore the logging can be seens as a warning ... 

If not - that is the 7910 is supposed to be able to run with one MPU in a normal setup. Then either:

1: They need to fix the software, so it can ignore the messages

or

2: Make the messages come a finite number of times, preferably less then 5.

because its a nuisance.

Regards

Søren Dideriksen, Network Administrator
Region Midtjylland
parnassus
Honored Contributor

Re: 7910 missing fan error message.

Just curious: are you speaking about two [*] JG843A or about two [**] JG844A?

AFAIK if one Switching Fabric Module is installed, then it requires just one Fan Tray (installed on the lower Fan Tray slot), if two Switching Fabric Modules are required then two Fan Trays are required too...and, generally, each Switching Fabric Module should always be installed below (and before) its related Fan Tray...starting from the lower (Slot 10 11, <-- read the Post below about these corrections) dedicated slot (with the upper slot panel filled if the second Switching Fabric Module - Slot 11 10 - and its Fan Tray are not required), the one near the PSUs slots at bottom...and if two Fan Trays are required...they should have the same SKU (so they both provide the same air flow direction).

[*] HPE FlexFabric 7910 Front (Port Side) to Back (Power Side) Airflow Fan Tray (JG843A): red handle, it exhausts warm air out of the 7910 Switch Chassis providing airflow from the port side (Front) to the power side (Rear)

[**] HPE FlexFabric 7910 Back (Power Side) to Front (Port Side) Airflow Fan Tray (JG844A): apparently with a red handle like the JG843A (shouldn't it use a blue handle instead to show that airflow direction is different as happens with the JG684A Fan Tray for the HPE FlexNetwor 7904)?, that SKU was recently added on QuickSpecs (June 2016), the airflow is the opposite with regard to the one provided by the JG843A.

Another curiosity, what display fan, display alarm and display environment and display power commands report?

VoIP-Buddy
HPE Pro

Re: 7910 missing fan error message.

So the issue here is that if you insert a fan tray into the hole without a fabric tray there are no power and monitoring connections.  The fan tray must be slid into a fabric tray as that provides the power and monitoring connections.

I had a 7910 running in my lab with 1 fabric and fan tray and it worked fine.  It did complain about a missing fan tray 2 but that was normal in that configuration.  I have since added another fabric and fan tray for redundancy and cooling.  No more error messages have been seen.  I think the fans also run at a more normal and quieter rate with two of them.

As I said previously, if you are going to run with 1 fabric and fan tray then you must block the hole for fabric and fan tray 2 or you will have cooling issues. 

Regards,

David

mekand
Occasional Advisor

Re: 7910 missing fan error message.

Hi.

I'm speaking about one JG843A and one MPU.

Installation guide is clear. Install MPU and FAN on the lower slot but something is wrong.

Slot 10 is on top and slot 11 is in the middle, near to PSUs. FAN1 slot is on top and FAN2 is near PSUs.

FAN1 led on MPU is red.

Syslog message appears to be right: FAN1 slot is empty!

VoIP-Buddy
HPE Pro

Re: 7910 missing fan error message.

It sounds like it is working as designed.  The red LED and messages will continue until you add a second fabric and fan assembly.  If not, the 7910 should run fine as it is now.

David

mekand
Occasional Advisor

Re: 7910 missing fan error message.

Thanks for your help David.

We have a 7910 with one MPU and relative FAN installed in the lower slot (slot11), near to PSUs.

MPU shows an error on FAN1, FAN1 led is red. Also a console message appears...

Is this a normal behavior?

Regards.

mekand
Occasional Advisor

Re: 7910 missing fan error message.

Good.

However, from my point of view, FAN1 should be in the lower slot and FAN2 in the upper slot.

Regards.

Andrea

VoIP-Buddy
HPE Pro

Re: 7910 missing fan error message.

Hi!

Yes.  I actually did the same thing with mine before I found out that there needs to be a second MPU and fan tray to shut off the warnings.

What you are seeing is what I would expect.  At some point you may want to consider adding the second MPU and fan tray so that you have redundancy with the switch fabric and more capacity.  if you don't, that's fine too.  The 7910 will be operationally happy.  :-)

Regards,

David

VoIP-Buddy
HPE Pro

Re: 7910 missing fan error message.

Yup.  I can see your point but... it is what it is. 

Regards,

David

mekand
Occasional Advisor

Re: 7910 missing fan error message.

Yuppy!

parnassus
Honored Contributor

Re: 7910 missing fan error message.

Last minute edit: in my post above I inverted the Slot 10 with 11 thinking that Slot 10 was the lower one in the Chassis...instead Slot 10 is clearly marked as the upper one and Slot 11 is clearly marked as the lower one (reference: Installation Guide)...but, if so, there is something strange in JG843A related Documentation...because Fan Tray installation guide doesn't says explicitly to install the first Fan Tray Slot (Fan Tray Slot 1) on the lowest Slot but say to leave the upper one free (covered):

"When one fan tray is required, install it in the lower fan tray slot. To maintain good ventilation, the upper fan tray slot must have a filler panel installed."

so the first Fan Tray should be placed on the lowest slot necessarily...exactly above the first Switching Fabric Module on Slot 11 leaving both upper slots (Fan Tray and second Switching Fabric Module slots) covered with a dedicated panel to let a correct airflow with just a single Fan Tray (as seen in various pictures)...at this point...that Fan Tray slot (Fan Tray slot 2) is the one that - in Installation guide - is related to the second Switching Fabric Module...so it seems that Installation Guide and Fan Tray Installation Guide aren't coherent about Fan Tray Modules <--> Fan Tray slots pairing...is that possible? Am I misunderstanding anything or am I doing a lot of confusion? gosh...

VoIP-Buddy
HPE Pro

Re: 7910 missing fan error message.

Yes, lower slot first.  I think it helps ventilation for the PSU's.

The important thing is that you insert the fabric tray first and then install the fan tray on top of that.  They then work together as a unit.

Regards,

David