Netra[TM] 240, Advanced Lights Out Management (ALOM) 1.5 reports that the AC Power Supply Unit is not properly seated, Service LED illuminated

Asset ID:	1-72-1017734.1
Update Date:	2017-11-30
Keywords:

Solution Type Problem Resolution Sure

Solution 1017734.1 : Netra[TM] 240, Advanced Lights Out Management (ALOM) 1.5 reports that the AC Power Supply Unit is not properly seated, Service LED illuminated

Applies to:

Sun Netra 240 (AC) Server - Version Not Applicable and later
Sun Netra 240 (DC) Server - Version Not Applicable and later
All Platforms

Symptoms

After installing ALOM 1.5 in Netra 240, the Service LED lights up.
If log into the ALOM (sc> prompt) from MGT port, one shall see:

Cause

N/A

Solution

sc> showenvironment

Environmental Status

.
.
.
-----------------------------------------------
Power Supplies:
-----------------------------------------------
Supply Status Underspeed Overtemp Overvolt Undervolt Overcurrent
-----------------------------------------------
PS0 NOT SEATED
PS1 NOT SEATED
.
.
.

that everyting looks normal but the PSUs (as indicated above:
NOT SEATED).

And the ALOM sends out the following alert messages:

SC Alert: PSU @ PS0 has FAILED.
SC Alert: PSU @ PS1 has FAILED.

and log the following lines repeatedly:

DEC 01 17:48:04 host: 00040082: "PSU @ PS0 is not properly seated."
DEC 01 17:48:04 host: 00040082: "PSU @ PS1 is not properly seated."
DEC 01 17:48:04 host: 00040066: "PSU @ PS0 has FAILED."
DEC 01 17:48:04 host: 00040066: "PSU @ PS1 has FAILED."

Regardless of how many times the PSUs are reseated the Service
LED stays ON and reporting of the condition persists.

This happens only if the following two components are present:

1) The 300-1568, 400W AC PSU, Type A178;

2) Advanced Lights Out Management (ALOM) 1.5 installed.

Resolution
The solution is implemented in ALOM 1.5.3.

ALOM 1.5.3 is released at Sun.Com download center:

http://www.sun.com/download/products.xml?id=415453f9

Relief/Workaround

It is understood how an illuminated Service LED can be disconcerting to system users, even though
they understand it's due to this benign issue.

However, this issue mitigates the value of the Service LED - that is to light when there is a serious system problem. Therefore, when this issue is evident the recommendation is to install ALOM 1.3.6. That is the next most recent ALOM version available for the Netra 240.

The issue described in this SRDB is not exhibited with ALOM 1.3.6.

Product
Netra 240 Server (AC)
Netra 240 Server

PSU has a pin called PS_KILL. It is used to write protect the upper 2K of the FRU SEEPROM.

The ALOM 1.5 algorithm for detecting a PSU seating problem is to write something/anything to this upper 2K --- a failure (unable to write) means the PSU is properly seated. A successful write means the PSU is not properly seated.

This PS_KILL pin "write protection" function is implemented in the DC PSU, NOT in the Type A178 AC PSU. Therefore, in the Type A178 AC PSU, ALOM 1.5 is able able to write successfully EVERYTIME, to the upper 2K of the FRU SEEPROM.

Therefore, it will always seem as though the AC PSU is not properly seated.

Earlier versions of ALOM do not use this algorithm. This issue will not be seen with the earlier ALOM versions.

The PS_KILL pin "write protection" function will be implemented in Type A192 AC PSU. That AC PSU type is not yet available for N240.

This issue is not seen in the V240 even though it uses the same Type A178 AC PSU. ALOM has a software switch to determine if the system is a V240 or N240. In a V240 ALOM 1.5 does not run the power supply seating detection algorithm. The PSU seating detection is implemented in the Netra 240 to enhance the NEBS earthquake requirement.

ALOM 1.5, PSU, Netra 240, Service LED
Previously Published As
79359

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