Troubleshooting the small disk enclosure system

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Alarm conditions

The following sections describe common problems that can occur with your small disk enclosure system, and some possible solutions. For the problems listed in the table below, the pertinent fault LEDs on the enclosure front panel will light amber to indicate a fault. See also Operator’s (Ops) panel.

Table 1. Alarm conditions
Status Severity Alarm
PCM alert – loss of DC power from a single PCM Fault – no loss of redundancy S1
PCM alert – loss of DC power from a single PCM Fault – loss of redundancy S1
PCM fan fail Fault – loss of redundancy S1
SBB module detected PCM fault Fault S1
PCM removed Configuration error None
Enclosure configuration error (VPD) Fault – critical S1
Low warning temperature alert Warning S1
High warning temperature alert Warning S1
Over temperature alarm Fault – critical S4
I2C bus failure Fault – loss of redundancy S1
Ops panel communication error (I2C) Critical fault S1
SBB interface module fault Fault – critical S1
SBB interface module removed Warning None
Drive power control fault Warning – no loss of drive power S1
Drive power control fault Fault– critical – loss of drive power S1
Insufficient power available Warning None
Note: For details on how to remove and replace a module see Chapter 6., “Module Removal and Replacement."

Power Cooling Module (PCM) faults

Table 2. Alarm conditions
Symptom Cause Action
Ops panel module fault LED amber Any power fault. Check AC mains connections to PCM is live.
Fan fail LED is illuminated on PCM. A fan failure. Replace PCM.

Thermal monitoring and control

The small disk enclosure system uses extensive thermal monitoring, and takes a number of actions to ensure component temperatures are kept low, and also to minimize acoustic noise. Air flow is from the front to the rear of the enclosure.

Table 3. Thermal monitoring and control
Symptom Cause Action
If the ambient air is below 25 °C and the fans are observed to increase in speed then some restrictionon airflow may be causing additional internal temperature rise.

Note: This is not a fault condition.

Thefirst stage in the thermal control process is for the fans to automatically increase in speed when a thermal threshold is reached. This may be caused by higher ambient temperatures in the local environment and may be perfectly normal.

Note: This threshold changes according to the number of drives and power supplies fitted.
  1. Check the installation for any airflow restrictions at either the front or rear of the enclosure. A minimum gap of 25mm at the front and 50mm at the rear is recommended.
  2. Check for restrictions due to dust build-up. Clean as appropriate.
  3. Checkf or excessive re-circulation of heated air from rear to the front. Use of the enclosure in a fully enclosed rack is not recommended.
  4. Check that all blank modules are in place and secure.
  5. Reduce the ambient temperature.

Thermal alarm

Table 4. Thermal alarm
Symptom Cause Action
  1. Ops panel modulefault LED is amber.
  2. Fan fail LED is lit on one or more PCMs.
 Internal temperature exceedsa pre-set threshold.
  1. Check that the local ambient environment temperature is below the specification.
  2. Check the installation for any airflow restrictions at either the front or rear of the enclosure. A minimum gap of 25mm at the front and 50mm at the rear is recommended.
  3. Check for restrictions due to dust build-up. Clean as appropriate.
  4. Check for excessive re-circulation of heated air from rear to the front. Use of the enclosure in a fully enclosed rack is not recommended.
  5. If possible shutdown the enclosure and investigate the problem before continuing.