Description

In rare cases, MX104 generates an SNMP trap for 'Fan/Blower Removed' even though no fan trays have been removed.

PR1223979 fixed an RE CPU hog software issue which triggered the 'Fan/Blower removed' and 'Fan/Blower OK' messages as well as various PEM errant alarms ( PEM not OK , PEM Temp High, PEM Input Failure ).

This article explains the issue and describes a means of determining whether there is a real issue with the fans.
 

Symptoms

Messages 

May 17 14:10:56  MX104_RE0 chassisd[1536]: CHASSISD_SNMP_TRAP6: SNMP trap generated: Fan/Blower Removed (jnxContentsContainerIndex 4, 
jnxContentsL1Index 1, jnxContentsL2Index 2, jnxContentsL3Index 0, jnxContentsDescr Fan 2, jnxOperatingState/Temp 2)

May 17 14:11:11  MX104_RE0 chassisd[1536]: CHASSISD_SNMP_TRAP6: SNMP trap generated: Fan/Blower OK (jnxContentsContainerIndex 4, 
jnxContentsL1Index 1, jnxContentsL2Index 2, jnxContentsL3Index 0, jnxContentsDescr Fan 2, jnxOperatingState/Temp 2)

 

Solution

Check if Junos software version has been fixed with PR1223979 - In MX104 platform: CPU hog or busy state will end up with sporadic I2C access error message and false alarms. This alarm should not be seen after fixing this PR. If the alarm is still seen for very short durations with no other logs (regardless of the Junos versions), the messages can be safely ignored as a transient problem. 

You will not see the message with the syslog filter configuration under syslog stanza. 

# set system syslog file messages match "!(.*Fan/Blower Removed.*|.*Fan/Blower OK.*)"

To determine if it is a real hardware problem, use the following steps. If there is an actual issue with the fans, then chassis alarms will be triggered.

  1. If there is a real issue with the fans, there should be an active alarm on the chassis like this: 

    MX104_RE0> show chassis alarms
1 alarms currently active
Alarm time               Class  Description
20yy-mm-dd yy:xx:zz UTC  Major  Fan Tray Failure

  2. If there are issues with the FAN/PEM, the status will be changed. Use the CLI command show chassis environment .

    By default, the status should be "OK". If there is a problem, the status will be changed to "not Ok" or "Check". 

    MX104_RE0> show chassis environment

Class Item                           Status     Measurement

Fans
      Fan 1                          Check
      Fan 2                          Check
      Fan 3                          Check
      Fan 4                          Check
      Fan 5                          Check

Modification History

2018-06-25: Added fix from PR1223979

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