Configuration Generation Performance Enhancement
First Published: March 2004
Last Updated: May 4, 2009
The Configuration Generation Performance Enhancement feature assists configuration management by enabling faster collection of running configuration file information. This feature is especially useful in managing large networks with numerous interfaces configured.
Finding Feature Information
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 for Configuration Generation Performance Enhancement" section.
Use Cisco Feature Navigator to find information about platform support and Cisco IOS XE software image support. To access Cisco Feature Navigator, go to http://www.cisco.com/go/cfn. An account on Cisco.com is not required.
Contents
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Restrictions for Configuration Generation Performance Enhancement
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Information About Configuration Generation Performance Enhancement
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How to Configure the Configuration Generation Performance Enhancement
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Configuration Examples for the Configuration Generation Performance Enhancement
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Additional References
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Feature Information for Configuration Generation Performance Enhancement
Restrictions for Configuration Generation Performance Enhancement
The device on which the Configuration Generation Performance Enhancement feature is used must have enough memory available to store (cache) a large interface configuration file. For example, if the interface configurations take up 15 KB of memory, using this feature would require having an additional 15 KB of memory space available.
Information About Configuration Generation Performance Enhancement
Before enabling the Configuration Generation Performance Enhancement feature, you should understand the following concepts:
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Cisco IOS XE Software Configuration Storage
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Benefits of the Configuration Generation Performance Enhancement
Cisco IOS XE Software Configuration Storage
In the Cisco IOS XE software configuration model, the configuration state is maintained in a distributed manner, with each component storing its own configuration state. To retrieve configuration information, the software must poll every component to collect the distributed information. This configuration state retrieval operation is performed by a process known as nonvolatile generation (NVGEN), and it is used by command-line interface (CLI) commands such as show running-configuration, write memory, and copy system:running-configuration to display or copy the running system configuration. When invoked, NVGEN queries each system component and each instance of interface or other configuration objects. A running configuration file is constructed as NVGEN traverses the system performing these queries.
Benefits of the Configuration Generation Performance Enhancement
Before the Configuration Generation Performance Enhancement feature was introduced, NVGEN always had to query the entire system and could generate only a total configuration. The time required to process the running configuration creates performance problems for configuration management, because completion of the NVGEN operation can take many minutes.
The Configuration Generation Performance Enhancement feature reduces the execution time for NVGEN processes and is especially useful for managing large configuration files that contain numerous interface configurations. This feature provides faster execution of commands that process the running system configuration by caching interface configuration information in system memory, and by retrieving only configuration information that has changed.
How to Configure the Configuration Generation Performance Enhancement
This section contains the following procedure:
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Configuring the Configuration Generation Performance Enhancement (required)
Configuring the Configuration Generation Performance Enhancement
Perform this task to enable the Configuration Generation Performance Enhancement.
SUMMARY STEPS
1.
enable
2.
configure terminal
3.
parser config cache interface
4.
end
DETAILED STEPS
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Step 1 |
enable
Router> enable |
Enables privileged EXEC mode. • Enter your password if prompted. |
Step 2 |
configure terminal
Router# configure terminal |
Enters global configuration mode. |
Step 3 |
parser config cache interface
Router(config)# parser config cache interface |
Reduces the time required for the CLI to execute commands that manage the running system configuration, especially for large configuration files. |
Step 4 |
end
Router(config)# end |
Exits global configuration mode and returns to privileged EXEC mode. |
Configuration Examples for the Configuration Generation Performance Enhancement
This section provides the following examples:
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Configuring the Configuration Generation Performance Enhancement: Example
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Verifying the Configuration Generation Performance Enhancement: Example
Configuring the Configuration Generation Performance Enhancement: Example
The following example shows how to enable the Configuration Generation Performance Enhancement feature:
Router(config)# parser config cache interface
Verifying the Configuration Generation Performance Enhancement: Example
You can verify that the parser config cache interface command has been enabled by checking for the command in the system configuration file displayed when you enter the show running-configuration EXEC command.
Note
The first time you display the configuration file, you will not see much evidence of improvement in performance because the interface cache will be filled up. However, you will notice performance improvements when you enter subsequent NVGEN-type commands such as the show running-configuration EXEC command.
Each time the interface configuration of an changes, the cache of the specified interface is flushed. The other interface data remains cached as before. Entering an NVGEN-type command after modifying the interface configuration will once again not show much evidence of improvement until the next NVGEN-type command is entered.
Router# show running-configuration
parser config cache interface
Additional References
The following sections provide references related to the Configuration Generation Performance Enhancement feature.
Related Documents
Standards
MIBs
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None |
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
Technical Assistance
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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 Configuration Generation Performance Enhancement
Table 1 lists the features in this module and provides links to specific configuration information.
Use Cisco Feature Navigator to find information about platform support and software image support. Cisco Feature Navigator enables you to determine which Cisco IOS XE software images support a specific software release, feature set, or platform. To access Cisco Feature Navigator, go to http://www.cisco.com/go/cfn. An account on Cisco.com is not required.
Note
Table 1 lists only the Cisco IOS XE software release that introduced support for a given feature in a given Cisco IOS XE software release train. Unless noted otherwise, subsequent releases of that Cisco IOS XE software release train also support that feature.
Table 1 Feature Information for the Configuration Generation Performance Enhancement Feature
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Configuration Generation Performance Enhancement |
Cisco IOS XE Release 2.1, 2.2, 2.3 |
The Configuration Generation Performance Enhancement feature assists configuration management by enabling faster collection of running configuration file information. This feature is especially useful in managing large networks with numerous interfaces configured. In Cisco IOS XE Release 2.1, this feature was introduced on Cisco ASR 1000 Series Routers. The following sections provide information about this feature: • Information About Configuration Generation Performance Enhancement • How to Configure the Configuration Generation Performance Enhancement Commands associated with this feature: • parser config cache interface • parser config partition • parser cache |
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