Memory Threshold Notifications
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Contents
- Memory Threshold Notifications
- Finding Feature Information
- Information About Memory Threshold Notifications
- Memory Threshold Notifications
- Memory Reservation
- 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
- Additional References
- Feature Information for Memory Threshold Notifications
Memory Threshold Notifications
The 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
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 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:
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:
How to Define Memory Threshold Notifications
Setting a Low Free Memory Threshold
- memory free low-watermark processor threshold
- memory free low-watermark io threshold
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. To reserve a region of memory to be used by the router for the issuing of critical notifications, perform the following steps:
DETAILED STEPS
Configuration Examples for Memory Threshold Notifications
Setting a Low Free Memory Threshold Examples
The following example specifies a threshold of 20000 KB of free processor memory before the router issues notifications:
Threshold for Free Processor Memory
Router(config)# memory free low-watermark processor 20000
The following example specifies a threshold of 20000 KB of free I/O memory before the router issues notifications:
Threshold for Free IO Memory
Router(config)# memory free low-watermark io 20000
If 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 20000k Pool: Processor Free: 66814056 freemem_lwm: 204800000
Once available free memory rises to above 5 percent of the threshold, another notification message like this is sent:
000032: *Aug 12 22:33:29.411: %SYS-5-FREEMEMRECOVER: Free Memory has recovered 20000k Pool: Processor Free: 66813960 freemem_lwm: 0
Additional References
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Technical Assistance
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Link |
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Feature Information for Memory Threshold Notifications
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 Memory Threshold Notifications |
| Feature Name |
Releases |
Feature Information |
|---|---|---|
| Memory Threshold Notifications |
12.2(18)S 12.0(26)S 12.3(4)T |
The 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. |
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