Broken Stack (Isolated Nodes)

When a stack setup is not properly unconfigured before the stacking cables are removed, former stack nodes can become isolated.

A common symptom of this problem is that either or both ends of a stacking link show that the state is No Neighbor. This can mean that the port at either end is configured incorrectly. Some configuration errors can produce the No Neighbor state at one end and the Link Down state at the other end.

Here is an example of how an isolated node would look when you log in to it:

 (pending-AAA) login:
Warning: the stack has no Master node and all active nodes are operating with
master-capability turned off. If you wish to reconfigure, you may log in using
the failsafe account. Alternatively, you may use the special login 
REBOOT AS MASTER-CAPABLE
with no password to force a reboot of a node with master-capability temporarily
turned on.

If the show stacking command shows the stack state for a slot as Active with the “O” flag set, the node associated with that slot might be isolated from the rest of the stack by a failed node.

To fix an isolated node problem, follow these steps:

Verify the physical connections between each port and the rest of the stack.
Following the prompt in the sample console session, log in by entering reboot as master-capable
The switch reboots as a master-capable switch.
Enter unconfigure stacking to unconfigure the stack.
This command takes effect only once. If the switch is powered off or rebooted you must reissue the reboot as master-capable command.