Description

This article explains the meaning of the 'Cmerror Op Set: PRECL:0:IX:* :  Chip IX-*,  instmem parity error detected in engine' syslog message along with the corresponding major alarm and clarifies whether any actions need to be taken.

Symptoms

Output of 'show system alarm' indicates 'Major Errors' alarm:

user@device> show chassis alarms
1 alarm currently active
Alarm time               Class  Description
2020-12-29 23:18:38 GMT  Major  FPC 0 Major Errors

The following log messages can be seen:

Dec 29 23:18:31  device : %PFE-5: fpc0 Error: /fpc/0/pfe/0/cm/0/PRECL:0:IX:0/0/PRECL_CMERROR_INSTMEM_PARITY_FAIL (0x340001), scope: pfe, category: functional, severity: major, module: PRECL:0:IX:0 , type: instmem parity error
Dec 29 23:18:31  device : %PFE-5: fpc0 Performing action get-state for error /fpc/0/pfe/0/cm/0/PRECL:0:IX:0/0/ PRECL_CMERROR_INSTMEM_PARITY_FAIL (0x340001) in module: PRECL:0:IX:0   with scope: pfe category: functional level: major
Dec 29 23:18:38  device : %PFE-5: fpc0 Performing action cmalarm for error /fpc/0/pfe/0/cm/0/PRECL:0:IX:0/0/PRECL_CMERROR_INSTMEM_PARITY_FAIL (0x340001) in module: PRECL:0:IX:0  with scope: pfe category: functional level: major
Dec 29 23:18:38  device alarmd[17986]: %DAEMON-4: Alarm set: FPC color=RED, class=CHASSIS, reason=FPC 0 Major Errors
Dec 29 23:18:38  device craftd[15838]: %DAEMON-4:  Major alarm set, FPC 0 Major Errors
Dec 29 23:18:38  device : %PFE-3: fpc0 Cmerror Op Set: PRECL:0:IX:0 :  Chip IX-0,  instmem parity error detected in engine 1

FPC syslog may indicate that memory parity errors keep increasing:

NPC0(device vty)# show syslog messages
[Dec 30 09:30:10.502 LOG: Info] precl_periodic_handler_generic: PRECL Chip:IX-0 current instruction memory parity error count: 35641
[Dec 30 09:30:10.502 LOG: Info] precl_ucode_re_download_prog: In PRECL Chip:IX-0 imem soft error correction action taken in eng:1
[Dec 30 09:30:11.502 LOG: Info] precl_periodic_handler_generic: PRECL Chip:IX-0 current instruction memory parity error count: 35642
[Dec 30 09:30:11.502 LOG: Info] precl_ucode_re_download_prog: In PRECL Chip:IX-0 imem soft error correction action taken in eng:1
[Dec 30 09:30:12.502 LOG: Info] precl_periodic_handler_generic: PRECL Chip:IX-0 current instruction memory parity error count: 35643
[Dec 30 09:30:12.502 LOG: Info] precl_ucode_re_download_prog: In PRECL Chip:IX-0 imem soft error correction action taken in eng:1
[Dec 30 09:30:13.502 LOG: Info] precl_periodic_handler_generic: PRECL Chip:IX-0 current instruction memory parity error count: 35644
[Dec 30 09:30:13.502 LOG: Info] precl_ucode_re_download_prog: In PRECL Chip:IX-0 imem soft error correction action taken in eng:1
[Dec 30 09:30:14.502 LOG: Info] precl_periodic_handler_generic: PRECL Chip:IX-0 current instruction memory parity error count: 35645
[Dec 30 09:30:14.502 LOG: Info] precl_ucode_re_download_prog: In PRECL Chip:IX-0 imem soft error correction action taken in eng:1
[Dec 30 09:30:15.502 LOG: Info] precl_periodic_handler_generic: PRECL Chip:IX-0 current instruction memory parity error count: 35646
[Dec 30 09:30:15.502 LOG: Info] precl_ucode_re_download_prog: In PRECL Chip:IX-0 imem soft error correction action taken in eng:1
[Dec 30 09:30:16.502 LOG: Info] precl_periodic_handler_generic: PRECL Chip:IX-0 current instruction memory parity error count: 35647
[Dec 30 09:30:16.502 LOG: Info] precl_ucode_re_download_prog: In PRECL Chip:IX-0 imem soft error correction action taken in eng:1
[Dec 30 09:30:17.502 LOG: Info] precl_periodic_handler_generic: PRECL Chip:IX-0 current instruction memory parity error count: 35648
[Dec 30 09:30:17.502 LOG: Info] precl_ucode_re_download_prog: In PRECL Chip:IX-0 imem soft error correction action taken in eng:1
[Dec 30 09:30:18.502 LOG: Info] precl_periodic_handler_generic: PRECL Chip:IX-0 current instruction memory parity error count: 35649
[Dec 30 09:30:18.502 LOG: Info] precl_ucode_re_download_prog: In PRECL Chip:IX-0 imem soft error correction action taken in eng:1
[Dec 30 09:30:19.502 LOG: Info] precl_periodic_handler_generic: PRECL Chip:IX-0 current instruction memory parity error count: 35650

Solution

This issue is caused by a memory read parity error condition. Here, the FPC has reported an IX-chip instruction memory parity error. A parity error is an error that results from irregular changes to data, as it is recorded when it is entered in memory.

There are two types of parity errors: soft parity errors and hard parity errors.

  • Soft parity errors are often caused by electromagnetic field conditions, such as background radiation, electromagnetic interference, or static discharge events.
  • Hard errors may be caused by power surges, overheating, manufacturing defects, or other causes.

Different types of parity errors can require re-transmission of data or cause serious system errors, such as system crashes.

This is typically a transient hardware issue with the IX-chip instruction memory, no RMA is required.

Collect the following outputs which may provide additional information regarding this issue:

  1.  Collect the ' show ' command output. 

    show log messages
start shell pfe network <fpcX>
show cmerror module brief
show cmerror module <module_number> error <error_id_number>
show syslog messages

  2. Analyze the show command output.

    In the show log messages file, review the events that occurred at or just before the appearance of the 'PRECL:0:IX:0 :  Chip IX-0,  instmem parity error detected in engine 1' line.

IX-chip is located on MIC, which means there are two possible ways to resolve this issue:

  1. FPC restart during a maintenance window.
  2. MIC restart during a maintenance window. MIC slot can be identified based on alarm - 'PRECL:0:IX: 0 ' means MIC in slot 0, and 'PRECL:0:IX: 2 ' means MIC in slot 1. Note that after MIC restart, the corresponding system alarm will not disappear. If there are no new alarm messages related to IX-chip in FPC syslog after MIC restart, the system alarm will need to be cleared manually using the clear chassis fpc errors command.

If the issue is seen repeatedly even after restarting the MIC or FPC, contact JTAC for further investigation and assistance.