Downloads |
 Feedback
|
Table Of Contents
Reserve Memory for Console Access
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
Configuring Reserve Memory for Console Access
Configuration Examples for Reserve Memory for Console Access
Configuring Reserve Memory for Console Access: Example
Feature Information for Reserve Memory for Console Access
Reserve Memory for Console Access
First Published: July, 22, 2002Last Updated: June 28, 2007The 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 in This Module
Your Cisco IOS software release may not support all of the features documented in this module. To reach links to specific feature documentation in this module and to see a list of the releases in which each feature is supported, use the "Feature Information for Reserve Memory for Console Access" section.
Finding Support Information for Platforms and Cisco IOS Software Images
Use Cisco Feature Navigator to find information about platform support and Cisco IOS software image support. Access Cisco Feature Navigator at http://www.cisco.com/go/fn. You must have an account on Cisco.com. If you do not have an account or have forgotten your username or password, click Cancel at the login dialog box and follow the instructions that appear.
Contents
•
Information About Reserve Memory for Console Access
•
•
•
Information About Reserve Memory for Console Access
Before you increase the amount of memory reserved for console access, you should understand the following concepts:
•
•
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 memory reserved console command provided by the Reserve Memory for Console Access feature.
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 dir nvram: command. For example, if the total number of used bytes of NVRAM displayed in the command dir nvram: 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 memory reserved console 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 show memory console reserved command.
How to Configure Reserve Memory for Console Access
This section provides contains the following procedure:
•
Configuring Reserve Memory for Console Access
Perform this task to configure reserve memory for console access. 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.
SUMMARY STEPS
1.
2.
3.
4.
5.
DETAILED STEPS
Examples
The following is sample output from the show memory console reserved command:
Router# show memory console reservedMemory reserved for console is 201400Configuration Examples for Reserve Memory for Console Access
This section provides the following configuration example:
•
Configuring Reserve Memory for Console Access: Example
The following example shows how to increase the reserve memory for console access to 1024 KB:
enable!configure terminal!memory reserved console 1024endThe following example shows how to disable the increase in reserved memory for the console access:
enable!configure terminal!no memory reserved consoleendAdditional References
The following sections provide references related to the Reserve Memory for Console Access feature.
Related Documents
Cisco IOS Configuration Fundamentals commands
Cisco IOS Configuration Fundamentals Command Reference, Release 12.2
Cisco IOS Configuration Fundamentals configuration tasks and concepts
Cisco IOS Configuration Fundamentals Configuration Guide, Release 12.2
Standards
No new or modified standards are supported by this feature, and support for existing standards has not been modified by this feature.
—
MIBs
RFCs
No new or modified RFCs are supported by this feature, and support for existing RFCs has not been modified for this feature.
—
Technical Assistance
Command Reference
This section documents modified commands only.
memory reserved console
To set the amount of memory reserved for console access, use the memory reserved console command in global configuration mode. To disable the change in memory reserved for console access, use the no form of this command.
memory reserved console number-of-kilobytes
no memory reserved console
Syntax Description
number-of-kilobytes
Amount of memory to be reserved in kilobytes. Minimum value is 1 KB and the maximum is 4096 KB.
Command Default
256 KB of memory is reserved for console use.
Command Modes
Global configuration
Command History
12.0(22)S
This command was introduced.
12.2(28)SB
This command was integrated into Cisco IOS Release 12.2(28)SB.
Usage Guidelines
Use the memory reserved console command to give a value greater than three times the number of used bytes in NVRAM. Use the dir nvram: command to compute the number of used bytes in NVRAM.
Examples
The following example shows how to increase the memory from the default 256 KB to 387 KB:
configure terminalmemory reserved console 387Related Commands
dir
Displays a list of files on a file system.
show memory console reserved
Displays the actual amount of memory that is reserved for router console use.
show memory console reserved
To display the actual amount of memory that is reserved for the router console, use the show memory console reserved command in user EXEC mode or privileged EXEC mode.
show memory console reserved
Syntax Description
This command has no arguments or keywords.
Command Modes
User EXEC
Privileged EXECCommand History
12.0(22)S
This command was introduced.
12.2(28)SB
This command was integrated into the Cisco IOS 12.2(28)SB release.
Examples
The following is sample output from the show memory console reserved command:
Router# show memory console reservedMemory reserved for console is 262144 bytesThe output shows that approximately 262 KB of memory is reserved for console use.
Related Commands
Feature Information for Reserve Memory for Console Access
Table 1 lists the release history for this feature.
Not all commands may be available in your Cisco IOS software release. For release information about a specific command, see the command reference documentation.
Cisco IOS software images are specific to a Cisco IOS software release, a feature set, and a platform. Use Cisco Feature Navigator to find information about platform support and Cisco IOS software image support. Access Cisco Feature Navigator at http://www.cisco.com/go/fn. You must have an account on Cisco.com. If you do not have an account or have forgotten your username or password, click Cancel at the login dialog box and follow the instructions that appear.
Note
Table 1 Feature Information for Reserve Memory for Console Access
Reserve Memory for Console Access
12.0(22)S
12.2(28)SBThe 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.
In 12.0(22)S, this feature was introduced.
In 12.2(28)SB, this feature was integrated into a Cisco IOS 12.2SB release.
The following sections provide information about this feature:
•
•
•
The following commands were modified by this feature: memory reserved console, show memory console reserved.
Any Internet Protocol (IP) addresses used in this document are not intended to be actual addresses. Any examples, command display output, and figures included in the document are shown for illustrative purposes only. Any use of actual IP addresses in illustrative content is unintentional and coincidental.
© 2002-2007 Cisco Systems, Inc. All rights reserved.
