A hardware mismatch between redundant supervisors and daughter cards causes this synchronization problem.
High availability redundancy minimizes the time taken to switch over from the active supervisor engine to the standby supervisor engine if the active supervisor engine fails. High availability redundancy provides startup and running configuration synchronization.
When high availability redundancy is enabled, the startup configuration of both of the Multilayer Switch Feature Cards (MSFCs) is updated if either of these commands is issued on the designated MSFC:
copy source startup-config
In systems with redundant supervisor engines (for example, the Cisco Catalyst 4500, 5500 and 6500 models), both of the supervisor engine types must be identical. To synchronize, the supervisor engines must have the same feature and daughter cards. This is an example for Cisco Catalyst 6500 models:
Mod MAC-Address(es) Hw Fw Sw --- ------------------------------------ ---- ----- ----------- 1 00-09-12-43-cf-4a to 00-09-12-43-cf-4b 7.2 5.3(1) 5.5(13a) 00-09-12-43-cf-48 to 00-09-12-43-cf-49 00-09-e9-7b-53-80 to 00-09-e9-7b-57-7f Cat6k (enable) show version WS-C6509-NEB Software, Version NmpSW: 5.5(13a) Copyright (c) 1995-2002 by Cisco Systems NMP S/W compiled on Feb 1 2002, 19:12:38
System Bootstrap Version: 5.3(1)
Hardware Version: 3.0 Model: WS-C6509-NEB Serial #: TBM06243597
Replace one of the supervisor engines so that the hardware configuration of both supervisors match. This needs to be the same model, with the same type of feature card and daughter card, if installed.
Perform these steps to replace a supervisor engine in high availability mode:
On the active supervisor engine, issue these two commands in the enable mode:
set system highavailability disable set system highavailability versioning disable (Only required if versioning is enabled)
Insert the standby supervisor engine card in the chassis. In approximately 120 seconds, the image that runs on the active supervisor engine is copied on the standby supervisor engine along with the boot variable. When the copy operation is complete, the standby module reloads and comes up the same code as the active one. During this period, the active supervisor engine works as usual.
Issue the show module command to check the status of the supervisor engines.
On the active supervisor engine, issue these commands to enable high availability:
set system highavailability enable set system highavailability versioning enable
When high availability is enabled, synchronization from the active to the standby supervisor engine begins, provided the standby supervisor engine is present and the software image version is compatible. When the image versioning option is enabled, and a standby supervisor engine and active supervisor engine run different images, Flash synchronization copies the image of the active supervisor engine to the image of the standby supervisor engine image and then restarts it. NVRAM synchronization occurs regardless of whether high availability is enabled or disabled, if there are compatible NVRAM versions on the two supervisor engines.