Logging to Local Nonvolatile Storage

Last Updated: October 12, 2011

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 router is rebooted.

Finding Feature Information

Your software release may not support all the features documented in this module. For the latest feature information and caveats, see 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 document.

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, refer to the Writing Logging Messages to Bootflash or a Harddisk, and to the Prerequisites for Logging to Local Nonvolatile Storage.

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, refer to the Copying Logging Messages to an External Disk.


Note
Logging to Local Nonvolatile Storage can use up to 2 GB of storage space.

Information About Logging to Local Nonvolatile Storage

The Logging to Local Nonvolatile Storage feature adds a router's bootflash or harddisk as a storage destination for logging messages. When using this feature, be sure to understand the following concepts:

System Logging Messages

System logging messages include error and debug messages generated by application programming interfaces (APIs) on the router. Typically, logging messages are stored in a router'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 router 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 Action Purpose
Step 1
enable


Example:

Router> enable

 

Enables privileged EXEC mode.

  • Enter your password if prompted.
 
Step 2
configure terminal


Example:

Router# configure terminal

 

Enables global configuration mode.

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


Example:

Router(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 from 4096 to 4294967295 bytes. 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:

Router(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 router's bootflash or a harddisk.

  • Before logging messages are written to a file on the bootflash or a harddisk, the Cisco IOS XE 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_11:26:2008::01:01:41.
Note    This feature supports only one log file per second due to its filename format, which contains timestamp suffix down to the seconds level.
 

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 Action Purpose
Step 1
enable


Example:

Router> enable

 

Enables privileged EXEC mode.

  • Enter your password if prompted.
 
Step 2
copy source-url destination-url


Example:

Router# 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

Writing Logging Messages to bootflash or a Harddisk Example

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:

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

Copying Logging Messages to an External Disk Example

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

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

Additional References

The following sections provide references related to the Logging to Local Nonvolatile Storage feature.

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

Standards

Standards

Title

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

--

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

RFCs

RFCs

Title

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

--

Technical Assistance

Description

Link

The Cisco Support website provides extensive online resources, including documentation and tools for troubleshooting and resolving technical issues with Cisco products and technologies.

To receive security and technical information about your products, you can subscribe to various services, such as the Product Alert Tool (accessed from Field Notices), the Cisco Technical Services Newsletter, and Really Simple Syndication (RSS) Feeds.

Access to most tools on the Cisco Support website requires a Cisco.com user ID and password.

http://www.cisco.com/techsupport

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 router is rebooted.

The following command was introduced or modified: logging persistent.

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