Remove Catalyst 9200 from a Stack

[MichaelGrech46995]

I have two Cisco Catalyst 9200's that are stacked.  We no longer need them stacked and wish to split them.  One switch will stay in production and the other will be reassigned later.  My thought to do this would be to power down the one switch no longer needed in the stack and disconnect it.  Essentially it will be like the switch failed, but I won't be replacing it.  Can they be split without powering down the other one staying in production?  Will it need to be rebooted?  Any CLI commands needed?  Thanks in advance for any help.

[Joseph W. Doherty · Accepted solution]

I believe that's an acceptable and safe way to remove one stack member.

If possible, take down the switch that's NOT the master.

Remember when you power on the removed switch, it will be a live "duplicate" of the other switch.  I.e. don't power back up unless not connected to prior network.  Clear switch config.

[Leo Laohoo · Accepted solution]

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@MichaelGrech46995 wrote:
Any CLI commands needed? 

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factory-reset config

[MichaelGrech46995]

Would that command be used on the switch I remove to set it back to defaults?
Also, would the switch that remains in production think it is still in a stack, and would need some type of reseting or "undoing the stack" commands?

[Leo Laohoo · Accepted solution]

1. Power down the switch meant for storage/spare. 
2. Remove all the stacking modules.  
3. Take the switch to a desk and power it up to erase the config.

[pieterh · Accepted solution]

yes the active switch only detects a member is down, but still thinks it is a stack
- "show switch" will give you details of the active switch number, with the other reported as "removed"
- show running-config | include provision  ! will give you the corresponding lines in the configuration  
- conf t
    no switch <x> provision .....    ! will remove the missing member from the configuration
    end
    write                                      ! (or copy running-config startup-config)   

NB! if you removed member 1 and member 2 remains, you may want to
- switch 2 renumber 1
   write
   reload                                    ! a reload is necessary to effectuate the renumbering

[Joseph W. Doherty]

BTW, a switch stack, with missing member isn't adverse to ongoing operation beyond stack being prepared for missing member to come back on-line.  (It's somewhat similar to a chassis switch when you pull out a line card.)

As @pieterh describes, you can remove the "ghost" config information.