Extend a MS210 stack.

[Anubizz]

Hi,

I'm about to extend a stack of two MS210 with another MS210. Both original members of the stack has one fiber uplink connection. Can I break the stack loop during production to add the third switch or do I need to ask for a service window? 

[KarstenI]

It is not supported that way:

https://documentation.meraki.com/MS/Stacking/Switch_Stacks#Physical_Switch_Stack_Configuration_Steps

But at least it worked here and there in the past to do it online. Better schedule a maintenance window or do it in a time of low usage.

[DarrenOC]

hi @Anubizz , some will argue you're fine to do it whilst live but personally I'd go for the outage window.  You could hit an issue when combining the stack so best to do whilst all offline.

[PhilipDAth]

I'm with @DarrenOC - don't do it live unless you really have no other choice.

Also, I would plug the switch in and leave it attached (via ordinary Gigabit Ethernet) to the network for a day beforehand.  This gives it plenty of time to upgrade its firmware.

Otherwise, if you just add it to the network and the stack you may be waiting a long time before it comes up.

[DarrenOC]

Good point on the firmware @PhilipDAth.