Resolution
Use these tips to prevent switch stack problems:
- Make sure the switches that you add to or remove from the switch stack are powered off.
- After you add or remove stack members, make sure that the switch stack operates at full bandwidth (32 Gbps).
Press the Mode button on a stack member until the Stack mode LED is on. The last two port LEDs on the switch should be green. Depending on the switch model, the last two ports are either 10/100/1000 ports or small form-factor pluggable (SFP) module ports. If one or both of the last two port LEDs are not green, the stack is not operating at full bandwidth.
- Use only one CLI session when you manage the switch stack. When using multiple CLI sessions to the stack master, commands that you enter in one session are not displayed in the other sessions. Therefore, it is possible that you might not be able to identify the session from which you entered a command.
- Manually assigning stack member numbers according to the placement of the switches in the stack can make it easier to remotely troubleshoot the switch stack. However, you will need to remember that the switches have manually assigned numbers if you add, remove, or rearrange switches later. Use the switch renumber global configuration command on the stack master to change the stack member number.
- If you replace a stack member with an identical model, the new switch functions with the exact same configuration as the replaced switch. This also assumes the new switch uses the same member number as the replaced switch.
- Removing powered-on stack members causes the switch stack to divide (partition) into two or more switch stacks, each with the same configuration. If you want the switch stacks to remain separate, change the IP address or addresses of the newly created switch stacks.
Complete these steps to recover from a partitioned switch stack:
- Power-off the newly created switch stacks.
- Reconnect them to the original switch stack through their StackWise ports.
- Power-on the switches.
For additional information, refer to the Preventing Switch Stack Problems section of Troubleshooting.
