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This chapter describes how to configure high availability, and describes the switchover processes.
Process restartability provides the high availability functionality in Cisco MDS 9000 Family switches. This process ensures that process-level failures do not cause system-level failures. It also restarts the failed processes automatically. This process is able to restore its state prior to the failure and continues executing from the failure point going forward.
Switchovers occur by one of the following two processes:
Once a switchover process has started another switchover process cannot be started on the same switch until a stable standby supervisor module is available.
This section includes the following topics:
The running image is automatically synchronized in the standby supervisor module by the active supervisor module. The boot variables are synchronized during this process.
The standby supervisor module automatically synchronizes its image with the running image on the active supervisor module.
Note The image a supervisor module is booted up from cannot be deleted from bootflash. This is to ensure that the new standby supervisor module ia able to synchronize during the process.
Be aware of the following guidelines when performing a manual switchover:
To manually initiate a switchover from an active supervisor module to a standby supervisor module, use the active supervisor module using Device Manager. After you enter this command, another switchover process cannot be started on the same switch until a stable standby supervisor module is available.
To perform a switchover using Device Manager, follow these steps:
Step 1 Ensure that an HA switchover is possible by selecting Physical > Modules to verify the presence of multiple modules.
You see the screen shown in Figure 2-1.
Figure 2-1 Modules Screen Shows Current Supervisor
Step 2 In the main Device Manager screen, select Admin > Reset Switch.
Figure 2-2 Reset Switch Dialog Box
Step 3 Click Switch to Standby.
The following conditions identify when automatic synchronization is possible:
Table 2-1 lists the possible values for the redundancy states.
Table 2-2 lists the possible values for the supervisor module states.
Table 2-3 lists the possible values for the internal redundancy states.
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The HA switchover mechanism in the standby supervisor module is enabled (see the “Synchronizing Supervisor Modules” section). |
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The active supervisor module in the switch is ready to be configured. The standby module is in the HA-standby state. |
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The switch is in the process of changing over to the HA switchover mechanism. |
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The switch is intentionally shut down for debugging purposes. |
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The standby supervisor module is in the process of synchronizing its state with the active supervisor modules. |
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The active supervisor module and the second supervisor module is present but is not functioning. |
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The switch is in a transient state. If it persists, call TAC. |