Redundant supervisor engines do not synchronize

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Wed, 07/22/2009 - 19:35
Jun 18th, 2009
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Core issue

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:

  • write memory
  • copy source startup-config


Resolution

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:

  • Slot 1 Supervisor Engine 2, PFC2, MSFC2
  • Slot 2 Supervisor Engine 2, PFC2, MSFC2 
  • Slot 1 Supervisor Engine 2, PFC2
  • Slot 2 Supervisor Engine 2, PFC2
  • Slot 1 Supervisor Engine 1, PFC, MSFC2
  • Slot 2 Supervisor Engine 1, PFC, MSFC2
  • Slot 1 Supervisor Engine 1, PFC, MSFC1
  • Slot 2 Supervisor Engine 1, PFC, MSFC1
  • Slot 1 Supervisor Engine 1, PFC
  • Slot 2 Supervisor Engine 1, PFC
  • Slot 1 Supervisor Engine 1
  • Slot 2 Supervisor Engine 1

To resolve this issue, perform these steps:

  1. Issue the show module and show version commands to determine the hardware configuration.

    In this example, although both supervisors are WS-X6K-SUP1A-2GE, the daughter cards do not match.

    For example, the show version command indicates that the daughter card on the slot 1 supervisor is a WS-F6020A, and the daughter card on the slot 2 supervisor is a WS-6K-PFC.

    Therefore, the status of the supervisor in slot 2 shows error in the show module output (instead of standby), and the supervisors cannot synchronize.

    This is an example:

    Cat6k (enable) show module
    Mod Slot Ports Module-Type               Model             Sub  Status

    --- ---- ----- -----------------------  ------------------ ---- -------
    1   1    2     1000BaseX Supervisor      WS-X6K-SUP1A-2GE   yes ok
    2   2    2     1000BaseX Supervisor      WS-X6K-SUP1A-2GE   yes error
    3   3    48    10/100BaseTX Ethernet     WS-X6348-RJ-45     no  ok
    4   4    48    10/100BaseTX Ethernet     WS-X6348-RJ-45     no  ok
    5   5    48    10/100BaseTX Ethernet     WS-X6348-RJ-45     no  ok
    6   6    48    10/100BaseTX Ethernet     WS-X6348-RJ-45     yes ok

    Mod Module-Name         Serial-Num
    --- ------------------- -----------
    1                       SAL062727YU
    2                       SAD0451015F
    3                       SAL06261UD7
    4                       SAL06261U3D
    5                       SAL06261U9C
    6                       SAL062518T5

    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

    Mod Port Model               Serial #    Versions
    --- ---- ------------------ ----------- --------------------------
    1   2    WS-X6K-SUP1A-2GE   SAL062727YU Hw : 7.2
                                             Fw : 5.3(1)
                                             Fw1: 5.4(2)
                                             Sw : 5.5(13a)
                                             Sw1: 5.5(13a)
              WS-F6020A          SAL062728J0 Hw : 2.0
    2   2    WS-X6K-SUP1A-2GE   SAD0451015F Hw : 7.0
                                             Fw : 5.3(1)
                                             Fw1: 5.4(2)
                                             Sw : 5.4(3)
                                             Sw1: 5.4(3)
             WS-F6K-PFC          SAD0451033T Hw : 1.1


       
  2. 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:

  1. 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)

  2. 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.

       
  3. 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.

       

To display the high availability configuration and operational states, issue the  show system highavailability command.

For more information, refer to the High Availability section of Configuring Redundancy.

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