High CPU alarm occurs on the CPM when a 'show tech-support' is generated

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Article ID: 167962

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Updated On:

Products

XOS

Issue/Introduction

High CPU utilization is caused by /crossbeam/bin/cbs_disk_usage script, which runs as part of show tech-support. Workaround is available to disable the script manually, and the fix is available is XOS versions 9.6.6 and 9.5.7High CPU usage alarm for the CPM is generated temporarily while the 'show tech-support' command is executed.
Log entries similar to below example are seen in /var/log/messages file:

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May 29 09:23:38 Pod10 cbshmonitord: [N] Violation (s=2, alarm) occurred 3 times: module:13, item:3503 (H_ID_PROC_HI_CORE_UTIL), time:"Wed May 29 09:23:28 2012", value: 98, norm:0-80, minor:0-90, major:0-99
May 29 09:23:38 Pod10 cbsalarmlogrd: AlarmID 593 | Wed May 29 09:23:38 2012 | major | cp1 | cpuCoreUtilizationExceeded | CPU utilization core: 1
May 29 09:23:38 Pod10 cbsalarmlogrd: AlarmID 594 | Wed May 29 09:23:38 2012 | info | system | systemAlarm | New system alarm level (major)
May 29 09:23:43 Pod10 cbshmonitord: [I] chassis fault counters: 0 1 0
May 29 09:23:43 Pod10 cbshmonitord: [N] Violation (s=1, no alarm) occurred: module:13, item:2905 (H_ID_MAJOR_LED_ON), time:[1332919423]"Wed May 28 09:23:43 2012"
May 29 09:23:48 Pod10 cbshmonitord: [N] Violation (s=1, alarm) occurred 3+ times: module:13, item:3503 (H_ID_PROC_HI_CORE_UTIL), time:"Wed May 28 09:23:48 2012"
May 29 09:23:48 Pod10 cbsalarmlogrd: AlarmID 595 | Wed Mar 29 09:23:48 2012 | minor | cp1 | cpuCoreUtilizationExceeded | CPU utilization core: 1
May 29 09:23:48 Pod10 cbsalarmlogrd: AlarmID 596 | Wed Mar 29 09:23:48 2012 | info | system | systemAlarm | New system alarm level (clear)
May 29 09:23:48 Pod10 cbsalarmlogrd: AlarmID 597 | Wed Mar 29 09:23:48 2012 | info | system | systemAlarm | New system alarm level (minor)

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Cause

The high CPU utilization is caused by the XOS script /crossbeam/bin/cbs_disk_usage, which runs as part of 'show tech-support' command. The cbs_disk_usage script identifies the top 5 large files on each VAP member within the /tftpboot directory.

 

Resolution

The fix for the issue has been implemented in XOS version 9.5.7 and 9.6.6, where the cbs_disk_usage script has been removed from 'show tech-support'.

Workaround

The script can be manually disabled using the following steps:

CBS# unix su
Password:

[[email protected] admin]# cd /crossbeam/bin
[[email protected] admin]# cp cbs_disk_usage cbs_disk_usage.orig
[[email protected] admin]# echo "echo SCRIPT cbs_disk_usage DISABLED TO AVOID HIGH CPU UTILIZATION" > cbs_disk_usage


Note - the script isn't used for anything else outside of "show tech-support" (and the backup version i.e. cbs_disk_usage.orig can be called manually if ever required).