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.

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

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.

Memory 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

Setting a Low Free Memory Threshold

Perform this task to set a low free memory threshold.

SUMMARY STEPS

  1. enable
  2. configure terminal
  3. memory free low-watermark [processor threshold

DETAILED STEPS

  Command or Action Purpose

Step 1

enable

Example:


Router> enable

Enables privileged EXEC mode.

  • Enter your password if prompted.

Step 2

configure terminal

Example:


Router# configure terminal

Enters global configuration mode.

Step 3

memory free low-watermark [processor threshold

Example:


Router(config)# memory free low-watermark processor 20000

Specifies a threshold in kilobytes of free processor memory. To view acceptable values for the memory threshold, enter the following command:

  • memory free low-watermark processor ?

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

  1. enable
  2. configure terminal
  3. memory reserve critical kilobytes

DETAILED STEPS

  Command or Action Purpose

Step 1

enable

Example:


Router> enable

Enables privileged EXEC mode.

  • Enter your password if prompted.

Step 2

configure terminal

Example:


Router# configure terminal

Enters global configuration mode.

Step 3

memory reserve critical kilobytes

Example:


Router(config)# memory reserve critical 1000

Reserves the specified amount of memory in kilobytes so that the router can issue critical notifications.

  • The amount of memory reserved for critical notifications cannot exceed 25 percent of total available memory.

Configuration Examples for Memory Threshold Notifications

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 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, the router sends a notification message like this one: 


000032: *Aug 12 22:33:29.411: %SYS-5-FREEMEMRECOVER: Free Memory has recovered 20000k
Pool: Processor  Free: 66813960  freemem_lwm: 0

Reserving 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

The amount of memory reserved for critical notifications cannot exceed 25 percent of total available memory.

Additional References

For additional information related to the CPU Thresholding Notification feature, refer to the following references:

Related Documents

Related Topic

Document Title

SNMP traps

Configuration Fundamentals Command Reference

Standards

Standards

Title

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

MIBs

MIBs Link

CISCO-PROCESS-MIB

To locate and download MIBs for selected platforms, Cisco IOS releases, and feature sets, use Cisco MIB Locator found at the following URL:

http://www.cisco.com/go/mibs

RFCs

RFCs

Title

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

Description

Link

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.

http://www.cisco.com/cisco/web/support/index.html

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

Cisco IOS XE Release 2.1

This feature was introduced on Cisco ASR 1000 Series Aggregation Services Routers.