Even if the enable stacking command executes without any warnings or prompts, it is still possible for a stack to fail.
When a stack fails, verify that all of the following conditions are met.
A common sign of a failed stack is one of the non-master nodes being stuck at (pending-AAA) for more than five minutes. You can attempt to communicate with the master node (the switch on which the stack was enabled) and determine what went wrong by checking the state of each slot in the stack, as shown in this example CLI session:
Slot-1 Stack.1 # show slot Slots Type Configured State Ports ---------------------------------------------------------- Slot-1 switch_model Operational 50 Slot-2 switch_model Failed 26 Slot-3 Empty 0 Slot-4 Empty 0 Slot-5 Empty 0 Slot-6 Empty 0 Slot-7 Empty 0 Slot-8 Empty 0
In this example, Slot-2 is in the failed state. To determine why it failed, enter the show slot command – in this example, show slot 2 – to get detailed information about the state of the failed slot:
Slot-1 Stack.1 # show slot 2 Slot-2 information: State: Failed Download %: 0 Last Error: License Mismatch Restart count: 1 (limit 5) Serial number: N/A(0) N/A(0) Hw Module Type: switch_model Configured Type: Ports available: 26 Recovery Mode: Reset Node MAC: 00:00:00:00:00:00 Current State: FAIL (License Mismatch) Image Selected: Image Booted: Primary ver: Secondary ver: Config Selected: NONE
In this example, the highlighted line in the output reveals the cause of the failure: a license mismatch in Slot-2.