Can you replace the master in a 3750 stack without rebooting?

[Michael Couture]

I have two like switches in a stack (WS-C3750G-48PS 15.0(1)SE2 C3750-IPBASEK9-M). Switch#1 is the master and is the one that needs to be replaced. Can I force Switch #2 to be the master, then power down switch#1, remove switch#1, insert the replacement, and then power on the newly added switch without shutting down or rebooting switch#2?

Thanks.

[Gregory Snipes · Accepted solution]

You do not need to force switch 2 to become the master. It will automatically be promoted to the master as soon as you disconnect switch 1. You can then attach the new switch to the stack. You will need to ensure the new switch is running the same (or at least compatible) software. You may need to renumber the new switch once it is in place.

[Michael Couture]

Thanks, for the feed back.

[Joseph W. Doherty]

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Posting

Just to add what Gregory has already described, switch two will remain master (until something causes another stack election).

By default, when there's a master change, gateway MACs change. This can confuse hosts that don't process the new master's gratuitous ARP.

There is a configuration option to retain the original master's MAC(s).