Logging to Local Nonvolatile Storage

The Logging to Local Nonvolatile Storage feature enables system logging messages to be saved on an advanced technology attachment flash disk. Messages saved on bootflash or a harddisk persist after a device is rebooted.

Finding Feature Information

Your software release may not support all the features documented in this module. For the latest caveats and feature information, see Bug Search Tool and the release notes for your platform and software release. To find information about the features documented in this module, and to see a list of the releases in which each feature is supported, see the feature information table at the end of this module.

Use Cisco Feature Navigator to find information about platform support and Cisco software image support. To access Cisco Feature Navigator, go to www.cisco.com/​go/​cfn. An account on Cisco.com is not required.

Prerequisites for Logging to Local Nonvolatile Storage

The logging buffered Command Must Be Enabled

Before the Logging to Local Nonvolatile Storage feature can be enabled with the logging persistent command, you must enable the logging of messages to an internal buffer with the logging buffered command. For additional information, see the "Writing Logging Messages to Bootflash or a Harddisk" section.

Restrictions for Logging to Local Nonvolatile Storage

Available Bootflash or Harddisk Space Constrains the Size and Number of Stored Log Files

The amount of bootflash or harddisk space allocated to system logging messages constrains the number of logging files that can be stored. When the allocation threshold is passed, the oldest log file in the directory is deleted to make room for new system logging messages. To permanently store system logging messages, you must archive them to an external device. For more information, see “Copying Logging Messages to an External Disk” section.


Note

Logging to local nonvolatile storage can use up to 2 GB of storage space.

Information About Logging to Local Nonvolatile Storage

System Logging Messages

System logging messages include error and debug messages generated by application programming interfaces (APIs) on the device. Typically, logging messages are stored in a device’s memory buffer; when the buffer is full, older messages are overwritten by new messages. All logging messages are erased from the memory buffer when the device reboots.

How to Configure Logging to Local Nonvolatile Storage

Writing Logging Messages to Bootflash or a Harddisk

Perform this task to enable the Logging to Local Nonvolatile Storage feature and write logging messages to bootflash or a harddisk.

SUMMARY STEPS

    1.    enable

    2.    configure terminal

    3.    logging buffered [buffer-size | severity-level]

    4.    logging persistent [url harddisk:/directory] [size filesystem-size] [filesize logging-file-size]


DETAILED STEPS
     Command or ActionPurpose
    Step 1 enable


    Example:
    Device> enable
     

    Enables privileged EXEC mode.

    • Enter your password if prompted.

     
    Step 2 configure terminal


    Example:
    Device# configure terminal
     

    Enables global configuration mode.

     
    Step 3 logging buffered [buffer-size | severity-level]


    Example:
    Device(config)# logging buffered
     

    Enables system message logging to a local buffer and limits messages logged to the buffer based on severity.

    • The optional buffer-size argument specifies the size of the buffer. Range is from 4096 to 4294967295. The default size varies by platform.

    • The optional severity-level argument limits the logging of messages to the buffer to those no less severe than the specified level.

     
    Step 4 logging persistent [url harddisk:/directory] [size filesystem-size] [filesize logging-file-size]


    Example:
    Device(config)# logging persistent url harddisk:/syslog size 134217728 filesize 16384
    Note   

    The default value is: url: bootflash:/syslog filesystem-size: 10% of total disk space logging-file-size: 262144

     

    Writes logging messages from the memory buffer to the specified directory on the device’s bootflash or a harddisk.

    • Before logging messages are written to a file on the bootflash or harddisk, the Cisco software checks to see if there is sufficient disk space. If not, the oldest file of logging messages (by timestamp) is deleted, and the current file is saved.

    • The filename format of log files is log_MM:DD:YYYY::hh:mm:ss. For example: log_11:26:2012::01:01:41.

    Note   

    This feature supports only one log file per second due to its filename format, which contains a timestamp suffix down to the seconds level.

    Note   
    The defaults for this command are as follows:
    • url: bootflash:/syslog Filesystem-size: 10% of total disk space. Logging-file-size: 262144
     

    Copying Logging Messages to an External Disk

    Perform this task to copy logging messages from the bootflash or a harddisk to an external disk.

    SUMMARY STEPS

      1.    enable

      2.    copy source-url destination-url


    DETAILED STEPS
       Command or ActionPurpose
      Step 1 enable


      Example:
      Device> enable
       

      Enables privileged EXEC mode.

      • Enter your password if prompted.

       
      Step 2 copy source-url destination-url


      Example:
      Device# copy harddisk:/syslog ftp://myuser/mypass@192.168.1.129/syslog
       

      Copies the specified file or directory on the bootflash or a harddisk via FTP to the specified URL.

       

      Configuration Examples for Logging to Local Nonvolatile Storage

      Example: Writing Logging Messages to Bootflash or a Harddisk

      The following example shows how to write up to 134217728 bytes (128 MB) of logging messages to the syslog directory of disk 0, specifying a file size of 16384 bytes: 

      Device(config)# logging buffered
Device(config)# logging persistent url harddisk:/syslog size 134217728 filesize 16384

      Example: Copying Logging Messages to an External Disk

      The following example shows how to copy logging messages from the device’s bootflash or harddisk to an external disk: 

      Device# copy harddisk:/syslog ftp://myuser/mypass@192.168.1.129/syslog

      Additional References

      Related Documents

      Related Topic

      Document Title

      copy command

      Cisco IOS Configuration Fundamentals Command Reference

      Network management commands (including logging commands): complete command syntax, defaults, command mode, command history, usage guidelines, and examples

      Cisco IOS Network Management Command Reference

      MIBs

      MIBs

      MIBs Link

      • No new or modified MIBs are supported by this feature, and support for existing MIBs has not been modified by this feature.

      To locate and download MIBs for selected platforms, Cisco IOS XE releases, and feature sets, use Cisco MIB Locator found at the following URL:

      http:/​/​www.cisco.com/​go/​mibs

      Technical Assistance

      Description

      Link

      The Cisco Support and Documentation website provides online resources to download documentation, software, and tools. Use these resources to install and configure the software and to troubleshoot and resolve technical issues with Cisco products and technologies. Access to most tools on the Cisco Support and Documentation website requires a Cisco.com user ID and password.

      http:/​/​www.cisco.com/​cisco/​web/​support/​index.html

      Feature Information for Logging to Local Nonvolatile Storage

      The following table provides release information about the feature or features described in this module. This table lists only the software release that introduced support for a given feature in a given software release train. Unless noted otherwise, subsequent releases of that software release train also support that feature.

      Use Cisco Feature Navigator to find information about platform support and Cisco software image support. To access Cisco Feature Navigator, go to www.cisco.com/​go/​cfn. An account on Cisco.com is not required.
      Table 1 Feature Information for Logging to Local Nonvolatile Storage

      Feature Name

      Releases

      Feature Information

      Logging to Local Nonvolatile Storage

      Cisco IOS XE Release 2.1

      The Logging to Local Nonvolatile Storage feature enables system logging messages to be saved on an advanced technology attachment flash disk. Messages saved on bootflash or a harddisk persist after a device is rebooted.

      The following command was introduced or modified: logging persistent.