Pillar Axiom: Slammer Fan Speed Warning

Asset ID:	1-72-1451422.1
Update Date:	2018-01-08
Keywords:

Solution Type Problem Resolution Sure

Solution 1451422.1 : Pillar Axiom: Slammer Fan Speed Warning

Applies to:

Pillar Axiom 500 Storage System - Version Not Applicable to Not Applicable [Release N/A]
Pillar Axiom 600 Storage System - Version Not Applicable and later
Pillar Axiom 300 Storage System - Version Not Applicable and later
Information in this document applies to any platform.

Symptoms

Slammer Fan Speed Warning Events, Callhomes, or ASR generated

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Cause

On Axiom release 3.1 and below, the Slammer Fan Speed Warning Event may be a spurious event due to noise on the i2C bus used to read the fan tachomer sensor. If the fan speed warning is a single event that does not recur, the cause is most likely software.

On Axiom release 3.2 and higher, including all R4 and R5 releases, the cause is the fan assembly or the monitoring and control circuit.

Solution

If a single highly intermittent fan speed warning event occurs on Axiom release 3.1 and below, an upgrade is recommended. The Slammer will report this event if a single reading of fan speed indicates an out of bounds value. If the fan speed warning event occurs twice in a single day, replace the fan assembly. The Axiom should be upgraded to current recommended releases to avoid false fan speed warnings.

Release 3.2 and all 4.x and 5.x perform 10 repeated readings and only generate the event if at least 3 readings are above or below fan speed thresholds.

The fan assembly generating the event is identified in the event details, which are available by clicking on the event in the GUI, or are also present in the callhome logs.

The Event will identify the Slammer, the Slammer Control Unit, and the two fan numbers of the fan assembly.

Fan 1 and Fan 2 are the left Fan Assemblies on the front of the CU
Fan 3 and Fan 4 are the right Fan Assemblies on the front of the CU.

Each Slammer control unit (CU) has two fan FRUs. The following figure shows a fan FRU, which is composed of a pair of fan assemblies. This means that each CU has four fan assemblies for cooling.

fan0

Note: When the fan FRU status shows that the FRU has failed, either fan assembly within the FRU may have failed. It is possible that the visible assembly in front is good while the rear assembly has failed. It is also possible that the good fan in the rear may cause the failed front fan blades to continue to rotate.

The following figure shows a Slammer face with the bezel removed, identifies the location of the Slammer fans.

Always use the Guided Maintenance screens when replacing the Fan Assembly. Detailed procedures are in the Service Guide which may be downloaded from the Axiom.

Select the Slammer named in the event and from the part and status details, select fan assembly 1 & 2 or 3 & 4, making sure the fan pair and CU number are the ones identified in the event. Follow the screens to identify the Slammer and part location and the replacement procedure.

In rare circumstances, the fan speed warning may be due to the fan control and sensor circuit which is located on the Slammer CU motherboard. The Fan Assembly should always be replaced first, and then if the Axiom is on release 3.2 or higher and the events continue, the CU motherboard should be replaced, using Guided Maintenance and the details in the Service Guide.

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