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Table Of Contents
Defining Memory Threshold Notifications
Information About Memory Threshold Notifications
Memory Threshold Notifications
How to Define Memory Threshold Notifications
Setting a Low Free Memory Threshold
Reserving Memory for Critical Notifications
Configuration Examples for Memory Threshold Notifications
Setting a Low Free Memory Threshold: Examples
Reserving Memory for Critical Notifications: Example
Feature Information for Memory Threshold Notifications
Defining Memory Threshold Notifications
First Published: August 21, 2003Last Updated: February 28, 2009The Memory Threshold Notifications feature allows you to reserve memory for critical notifications and to configure a router to issue notifications when available memory falls below a specified threshold.
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 Memory Threshold Notifications" section.
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.
Contents
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Information About Memory Threshold Notifications
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Information About Memory Threshold Notifications
The Memory Threshold Notifications feature provides two ways to mitigate low-memory conditions on a router: notifications can be sent to indicate that free memory has fallen below a configured threshold, and memory can be reserved to ensure that sufficient memory is available to issue critical notifications. To implement the Memory Threshold Notifications feature, you should understand the following concepts:
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Memory Threshold Notifications
Notifications are messages issued by the router. When you specify a memory threshold using the memory free low-watermark command, for example, the router issues a notification when available free memory falls below the specified threshold, and again once available free memory rises to 5 percent above the specified threshold. The following are examples of memory threshold notifications:
Available Free Memory Less Than the Specified Threshold
000029: *Aug 12 22:31:19.559: %SYS-4-FREEMEMLOW: Free Memory has dropped below 2000kPool: Processor Free: 66814056 freemem_lwm: 204800000Available Free Memory Recovered to More Than the Specified Threshold
000032: *Aug 12 22:33:29.411: %SYS-5-FREEMEMRECOVER: Free Memory has recovered 2000kPool: Processor Free: 66813960 freemem_lwm: 0Memory Reservation
Memory reservation for critical operations ensures that management processes, such as event logging, continue to function even when router memory is exhausted.
How to Define Memory Threshold Notifications
This section contains the following procedures:
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Setting a Low Free Memory Threshold
Perform this task to set a low free memory threshold.
SUMMARY STEPS
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DETAILED STEPS
Reserving Memory for Critical Notifications
When a router is overloaded by processes, the amount of available memory might fall to levels insufficient for it to issue critical notifications. Perform this task to reserve a region of memory to be used by the router for the issuing of critical notifications.
SUMMARY STEPS
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DETAILED STEPS
Configuration Examples for Memory Threshold Notifications
This section provides the following configuration examples:
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Setting a Low Free Memory Threshold: Examples
Threshold for Free Processor Memory
The following example shows how to specify a threshold of 20000 KB of free processor memory before the router issues notifications:
Router(config)# memory free low-watermark processor 20000If available free memory falls below the specified threshold, the router sends a notification message like this one:
000029: *Aug 12 22:31:19.559: %SYS-4-FREEMEMLOW: Free Memory has dropped below 20000kPool: Processor Free: 66814056 freemem_lwm: 204800000Once available free memory rises to above 5 percent of the threshold, the router sends a notification message like this one:
000032: *Aug 12 22:33:29.411: %SYS-5-FREEMEMRECOVER: Free Memory has recovered 20000kPool: Processor Free: 66813960 freemem_lwm: 0Reserving Memory for Critical Notifications: Example
The following example shows how to reserve 1000 KB of memory for critical notifications:
Router# memory reserved critical 1000
Note
Additional References
The following sections provide references related to the Memory Threshold Notifications feature.
Related Documents
Cisco IOS XE commands
For information about Cisco IOS XE commands, use the Command Lookup Tool at http://tools.cisco.com/Support/CLILookup or the Cisco IOS Master Command List, All Releases, at http://www.cisco.com/en/US/docs/ios/mcl/allreleasemcl/all_book.html.
Standards
No new or modified standards are supported by this feature and support for existing standards has not been modified by this feature.
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MIBs
RFCs
No new or modified RFCs are supported by this feature and support for existing RFCs has not been modified by this feature.
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Technical Assistance
Feature Information for Memory Threshold Notifications
Not all commands may be available in your Cisco IOS software release. For release information about a specific command, see the command reference documentation.
Use Cisco Feature Navigator to find information about platform support and software image support. Cisco Feature Navigator enables you to determine which Cisco IOS and Catalyst OS 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
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