System Management Configuration Guide for Cisco 8000 Series Routers, Cisco IOS XR Releases

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System Management Configuration Guide for Cisco 8000 Series Routers, Cisco IOS XR Releases

Core dump folder limits

Updated: June 12, 2026

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Explains how configurable core dump folder limits in Cisco IOS XR control diagnostic file storage, automate cleanup, and help safeguard system reliability.

A core dump folder limit is a storage management feature that

  • enables administrators to control the amount of disk space used for storing core dump diagnostic files,

  • enforces the maximum number of coreinfo files retained in the core dump directory, and

  • automates periodic cleanup and disk usage monitoring to prevent data loss during system failures.

Before Cisco IOS XR Release 25.2.1, the core dump folder lacked a storage limit, which meant repeated system crashes could fill all allocated disk space, preventing newer core files from being saved and resulting in potential data loss.

From Release 25.2.1, Cisco IOS XR supports the following mechanisms to manage core dump folder usage:

  • Disk usage limit: Use the exception disk-usage-limit <usage limit percent> command to set core dumps to fill only 20% to 50% of the disk space.

  • Throttling mechanism bypass: Use the exception filepath command to redirect core files to another directory, enabling new storage locations.

  • Periodic cleanup: The system automatically checks the core dump folder every 15 minutes and deletes the oldest coreinfo files if their count exceeds 50, focusing on files like those ending with .core.txt.

  • Syslog alerts: Syslog messages notify administrators when limits are reached, or automatic cleanup occurs, maintaining disk health and alerting to critical storage events.

Restrictions of core dump folder limit

To ensure proper handling of core dumps in Cisco IOS XR, adhere to the following requirements:

  • If available disk space is less than 10 percent of the hard drive, the system aborts the core file copy and deletes the file from the temporary directory.

  • If the core dump folder exceeds the configured disk usage threshold and the most recent core file is within 10 minutes of the latest system crash, the system aborts saving new core files and deletes incoming files.

Examples:

  • When available disk space is below 10 percent:

    • The system aborts the core file copy and deletes the core file from /misc/scratch/core.

      Example syslog message: 
      Router: Jan 31 10:18:42.000 UTC: dumper[1759]:
                  %INFRA-CALVADOS_DUMPER-2-ABORT_COPY : Copy of
                  sleep_16135.by.3.20250131-101800.ios.34684.core.lz4 to 0/RP0:/misc/disk1/coredumps
                  aborted for reason: Not enough available space in /misc/disk1 (less than 10%).
                  Deleting core from /misc/scratch/core

  • When disk usage exceeds the folder limit and prior core dump is within 10 minutes of current crash:

    • The system aborts the core file copy and deletes the core file from /misc/scratch/core.

    • Example syslog message: 

      Router: Mar 25 05:53:08.000 UTC: dumper[2715]:
                  %INFRA-CALVADOS_DUMPER-2-ABORT_COPY : Copy of
                  sleep_21216.by.3.20380325-055224.ios.34684.core.lz4 to
                  0/RSP0:/misc/disk1/coredumps aborted for reason: Dumper disk usage exceeds 20%
                  threshold of /misc/disk1. Deleting core from /misc/scratch/core

How core dump folder limit works

Summary

Cisco IOS XR software manages core dump storage by monitoring disk usage in the core dump folder and enforcing configured folder limits. When certain disk usage thresholds are reached, the software deletes older core files or aborts saving new files to maintain storage integrity and prevent failures.

  • The key components involved in the process are:

    • Cisco IOS XR software: Monitors disk usage and manages core file storage based on configured limits.

    • Core dump folder: Stores the core files created during system crashes.

    • Core files: Files generated during system crashes for troubleshooting and analysis.

Workflow

The process involves these stages:

  1. Continuous monitoring: Cisco IOS XR software continuously monitors the disk usage of the core dump folder against the configured limit.
  2. Exceeding disk usage limit and files older than 10 minutes:
    • If the core dump folder storage size exceeds the configured disk usage limit and the latest core file is more than 10 minutes older than the current crash time, the software deletes older core files (starting from oldest to newest) until storage usage falls below the configured limit. Example syslog messages: 
      Jan 21 10:19:36.251 UTC: dumper[399]: %OS-COREHELPER-6-DELETE_STALE_CORE :
              Deleting /misc/disk1/coredumps/ sleep_10432.by.3.20250121-100007 ... Freeing up old
              core in /misc/disk1/coredumps, attempting to copy new core file
  3. Exceeding disk usage limit and files within 10 minutes of crash time:
    • If storage exceeds the configured limit but the latest core file is within 10 minutes of the current crash time, the software aborts saving new core files and deletes any incoming files. Example syslog messages: 
      Jan 24 10:23:53.921 UTC: dumper[175]: %OS-COREHELPER-2-ABORT_COPY : Copy of core
              file aborted for reason: Dumper disk usage exceeds 20% threshold of /misc/disk1.
              Potential usage with new core: 100.0%
  4. Hard disk usage exceeds 90%:
    • If the overall hard disk is filled more than 90%, the software aborts saving and deletes any incoming core files, as it cannot delete any old files to free up space.Example syslog messages: 
      Mar 25 04:25:06.252 UTC: dumper[329]: %OS-COREHELPER-2-ABORT_COPY : Aborted copy
              due to insufficient available space; deleting incoming core file.

Result

Cisco IOS XR software ensures that core dump storage does not exceed configured limits, maintaining system stability and preventing disk overflow. Old files are deleted or new files are blocked when necessary, with syslog messages generated for each action.

Configure core dump folder limit

Limit the percentage of hard disk space used for core dumps to maintain available storage and system performance.

By controlling the storage allocation for core dumps, you prevent the system from using excessive disk space, which can affect system operation.

Procedure

1.

Set the core dump folder storage limit to prevent excessive core dumps on the hard disk.

Example:

Router#configuration
Router(config)#exception disk-usage-limit 29
Router(config)#commit

You can configure the core dump folder storage limit to range between 20 and 50 percent of the total hard disk space.
2.

Verify the configured core dump folder storage limit.

Example:

This example displays the core dump folder storage limit set to 29 percent of the total hard disk space. 
Router#show exception
 Exception path for choice 1 is not configured or removed 
 Exception path for choice 2 is not configured or removed 
 Exception path for choice 3 is not configured or removed 
 Default fallback/copy path = /misc/disk1/coredumps
 Core dump usage on disk limited to 29%

Example:

This example displays the core dump folder storage limit reset to 20 percent of the total hard disk space after disabling the exception disk-usage-limit command. 
Router#show exception
Exception path for choice 1 is not configured or removed 
Exception path for choice 2 is not configured or removed 
Exception path for choice 3 is not configured or removed
Default fallback/copy path = /misc/disk1/coredumps
Core dump usage on disk limited to 20%

The router restricts core dump storage usage to the configured percentage of total disk space, preventing excessive disk consumption.

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