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Contents
- Reserve Memory for Console Access
- Finding Feature Information
- Information About Reserve Memory for Console Access
- More Reserved Memory for Console Access Benefit
- Guidelines for Increasing Reserved Memory for Console Access
- How to Configure Reserve Memory for Console Access
- Examples
- Configuration Examples for Reserve Memory for Console Access
- Example Configuring Reserve Memory for Console Access
- Additional References
- Feature Information for Reserve Memory for Console Access
Reserve Memory for Console Access
The Reserve Memory for Console Access feature implements command-line interface (CLI) and software enhancements that allow you to reserve sufficient memory to log in to the router console and perform administrative tasks and troubleshooting. These enhancements give administrators the ability to log in to the router in any situation even when the router is running low on memory.
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.
Information About Reserve Memory for Console Access
- More Reserved Memory for Console Access Benefit
- Guidelines for Increasing Reserved Memory for Console Access
More Reserved Memory for Console Access Benefit
Before the release of Cisco IOS 12.0(22)S software, you could not access the router console if a router was low on memory or was heavily fragmented. To maintain routers at optimum performance levels, you need to be able to access the console and perform troubleshooting when necessary.
With the release of the Reserve Memory for Console Access feature, the benefit is that you can reserve sufficient memory to log in to the router console and perform administrative tasks and troubleshooting in any situation, even when the router is running low on memory or is heavily fragmented.
Guidelines for Increasing Reserved Memory for Console Access
Cisco IOS software reserves a default of 256 kilobyte (KB) of memory for console access. You can increase the reserved memory through the use of the memoryreservedconsole command provided by the Reserve Memory for Console Access feature.
You may need to increase the amount of memory reserved for console access if the router is low on memory or is heavily fragmented. Increasing the memory allows console access to perform troubleshooting or other administrative tasks to maintain routers at optimum performance levels.
The guideline we suggest for using the command is to configure a value greater than three times the number of the used bytes in NVRAM. You can obtain the number of used bytes in NVRAM from the output of the dirnvram: command. For example, if the total number of used bytes of NVRAM displayed in the command dirnvram:output is 129016 bytes, the nearest kilobyte value rounded off is 129 KB. This value multiplied by 3 is 387 KB. Following the guideline, you would enter 387 as the value for the number-of-kilobytes argument in the memoryreservedconsole command. You can increase the reserved memory for console access to a maximum of 4096 KB.
To display the current operational size of the memory reserved for the console, you can use the showmemoryconsolereserved command.
How to Configure Reserve Memory for Console Access
DETAILED STEPS
Configuration Examples for Reserve Memory for Console Access
Example Configuring Reserve Memory for Console Access
The following example shows how to increase the reserve memory for console access to 1024 KB:
enable ! configure terminal ! memory reserved console 1024 end
The following example shows how to disable the increase in reserved memory for the console access:
enable ! configure terminal ! no memory reserved console end
Additional References
Related Documents
MIBs
Technical Assistance
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Description |
Link |
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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. |
Feature Information for Reserve Memory for Console Access
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 Reserve Memory for Console Access |
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Feature Name |
Releases |
Feature Information |
|---|---|---|
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Reserve Memory for Console Access |
12.0(22)S 12.2(28)SB 12.4(15)T |
The Reserve Memory for Console Access feature implements command-line interface (CLI) and software enhancements that allow you to reserve sufficient memory to log in to the router console and perform administrative tasks and troubleshooting. These enhancements give administrators the ability to log in to the router in any situation even when the router is running low on memory. The following commands were modified by this feature: memory reserved console,show memory console reserved. |
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Any Internet Protocol (IP) addresses and phone numbers used in this document are not intended to be actual addresses and phone numbers. Any examples, command display output, network topology diagrams, and other figures included in the document are shown for illustrative purposes only. Any use of actual IP addresses or phone numbers in illustrative content is unintentional and coincidental.