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Table Of Contents
Related Features and Technologies
Supported Standards, MIBs, and RFCs
Verifying Post-Switchover Core Dump
Post-Switchover Core Dump
Feature History
This document describes the Post-Switchover Core Dump feature in Cisco IOS Release 12.0(18)ST. It includes the following sections:
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Supported Standards, MIBs, and RFCs
Feature Overview
When a Route Processor (RP) crashes, it is sometimes useful to obtain a full copy of the memory image (called a core dump) to identify the cause of the crash. (Not all crash types will produce a core dump.)
In networking devices that support redundant RPs, one processor acts as the active processor while the other processor acts as the standby processor. In the event of a crash, the standby processor switches over to become the active processor. The Post-Switchover Core Dump feature allows the newly active processor to complete the switchover process before writing the core dump information from the previously active processor to a preconfigured file.
Core dumps are generally useful only to your technical support representative. The core dump file, which is a very large binary file, must be transferred using the Trivial File Transfer Protocol (TFTP), File Transfer Protocol (FTP), or remote copy protocol (rcp) server and subsequently interpreted by your Cisco Technical Assistance Center (TAC) representative who has access to source code and detailed memory maps.
The Post-Switchover Core Dump feature does not introduce any new commands and uses existing exception commands to configure dump parameters in the configuration file. It does, however, identify a specific processor core dump for a networking device with redundant processors by appending a processor slot number at the end of the core dump filename.
Caution
Benefits
Decreases Switchover Time
In networking devices with redundant processors, the Post-Switchover Core Dump feature uses better software communication techniques between redundant processors to allow the switchover to occur before dumping core information. Not having to wait for dump operations effectively decreases the switchover time between processors. The newly active primary processor runs the core dump operation after switchover.
Restrictions
Restrictions or limitations previously associated with the exception commands still apply.
The Cisco IOS software image on the newly active processor must be compatible (12.0(18)ST or later) with the software running on the previously active processor.
You can configure a networking device to use any of four different methods to generate a core dump: TFTP, FTP, rcp, and Flash disk. Of these protocols, rcp is not recommended due to its slower transfer rate.
Related Features and Technologies
No new commands or configuration tasks were implemented for this feature. For information on how to configure the networking device for a core dump, refer to "Troubleshooting the Router" in the "System Management" part of the Cisco IOS Configuration Fundamentals Configuration Guide, Release 12.0.
Related Documents
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Supported Platforms
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Platform Support Through Feature Navigator
Cisco IOS software is packaged in feature sets that support specific platforms. To get updated information regarding platform support for this feature, access Feature Navigator. Feature Navigator dynamically updates the list of supported platforms as new platform support is added for the feature.
Feature Navigator is a web-based tool that enables you to quickly determine which Cisco IOS software images support a specific set of features and which features are supported in a specific Cisco IOS image.
To access Feature Navigator, you must have an account on Cisco.com. If you have forgotten or lost your account information, send a blank e-mail to cco-locksmith@cisco.com. An automatic check will verify that your e-mail address is registered with Cisco.com. If the check is successful, account details with a new random password will be e-mailed to you. Qualified users can establish an account on Cisco.com by following the directions at http://www.cisco.com/register.
Feature Navigator is updated when major Cisco IOS software releases and technology releases occur. As of May 2001, Feature Navigator supports M, T, E, S, and ST releases. You can access Feature Navigator at the following URL:
http://www.cisco.com/go/fn
Supported Standards, MIBs, and RFCs
Standards
None
MIBs
None
To obtain lists of supported MIBs by platform and Cisco IOS release, and to download MIB modules, go to the Cisco MIB website on Cisco.com at the following URL:
http://www.cisco.com/public/sw-center/netmgmt/cmtk/mibs.shtml
RFCs
None
Prerequisites
Redundant RPs must be running Cisco IOS Release 12.0(18)ST or later.
Configuration Tasks
None
No new commands or configuration tasks were implemented for this feature. Refer to "Troubleshooting the Router" in the "System Management" part of the Cisco IOS Configuration Fundamentals Configuration Guide, Release 12.0, for information on how to configure the networking device for a core dump.
Verifying Post-Switchover Core Dump
Step 1
Step 2
Step 3
Troubleshooting Tips
The Core Dump Process Appears Slow
Check that the software images running on the processors are compatible. If for any reason the Cisco IOS software image on the newly active processor is incompatible with the software image running on the previously active processor, the Post-Switchover Core Dump feature will not use the newly active processor for dumping the system core information. Instead, the failed processor will use existing processes for writing the core file to Flash memory or to a network file; however, this method will slow down the switchover process. Contact your Cisco TAC representative for assistance.
The Core Dump File Is Missing
If the Cisco software image on the newly active processor software is compatible with the software running on the previously active processor, but the processor-to-processor communication is not successful, the core dump information will not be written to a file. Contact your Cisco TAC representative for assistance.
Line Card Dump Information Is Taking a Long Time
If the networking device experiences one or more line card failures at the same time that the newly active primary processor is writing the core dump information from the failed primary processor, the line card information will be written to a file; however, this process might take more time than for a failed RP alone. Contact your Cisco TAC representative for assistance.
Configuring rcp Transfer Appears to Slow Down the Switchover
You can configure a networking device to use any of four different methods to generate a core dump: TFTP, FTP, rcp, and Flash disk. Of these protocols, rcp is not recommended due to its slower transfer rate.
The Slot Number Is Not Appended to the Dump File
The Post-Switchover Core Dump feature adds the slot number to the core dump file to identify which processor generated the file content. If the slot number is not appended to the filename, it could indicate that either the processors are not communicating or the software images running on the processors are incompatible. Contact your Cisco TAC representative for assistance.
Configuration Examples
None
No new commands or configuration tasks were implemented for this feature. For information on how to configure the networking device for a core dump, refer to "Troubleshooting the Router" in the "System Management" part of the Cisco IOS Configuration Fundamentals Configuration Guide, Release 12.0.
Command Reference
None
The Post-Switchover Core Dump feature introduces no new commands.
