Add a stack to an existing switch

[Robbo1882]

We have and existing switch in the dashboard configured doing it's thing but I have bought a new switch and want to physical stack them to together.

Is this straight forward or do I need to take steps so I don't wipe the existing config from the old switch?

I have bought the stacking cables and ready to stack them but it just wanted to double check that connecting new switch and inserting the stacking cables, then creating the stack in the dashboard it won't wipe the config from the existing switch.

Also do both switches need to be powered off to connected the stacking cables or can the switches be powered on?

[alemabrahao]

Take a look at this:

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

[alemabrahao]

And also this:

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

[Robbo1882]

Thanks for the links, but it doesn't mention anything about adding a new switch to one that has been in the network for some time and is currently the core of the network, by adding a new switch in and creating a stack I don't want to lose the config on the existing switch. 

I want to add a some redundancy to the network hence adding a new switch and creating a stack.

[KarstenI]

You will not lose the config of the existing switch. But adding a member to a stack (or especially building a stack) is better done with the switches being switched off and not doing it online.

[alemabrahao]

Are you sure?

When a new switch stack is created, or a new switch is added to an existing stack, the below configurations will be removed from the stand-alone switch(es) and will need to be reconfigured on the stack:

• Link aggregates
• Mirrored ports
• SVIs
• IGMP snooping (if switch specific settings are configured)
• MTU size (if switch specific settings are configured)
• STP priority (if switch specific settings are configured)

Features like the ones above run one instance for the entire switch. When a stack is created, you are combining multiple physical switches all running their own instances of the feature to a single logical switch, which is why some features need to be reconfigured. 

[alemabrahao]

Physical Switch Stack Configuration Steps 

The steps below explain how to prepare a group of switches for physical stacking, how to stack them together, and how to configure the stack in Dashboard.

1. Add the switches into a Dashboard network. This can be a new Dashboard network for these switches, or an existing network with other switches. Do not configure the stack in Dashboard yet.
2. Connect each switch with individual uplinks to bring them both online and ensure they can check in with the Meraki Dashboard.
3. Download the latest firmware build using the Firmware Upgrade Manager under Organization > Monitor > Firmware Upgrades, if they are not already set for this. This helps ensure each switch is running the same firmware build.
4. With all switches powered off and links disconnected, connect the switches together via stacking cables in a ring topology (as shown in the following image). To create a full ring, start by connecting switch 1/stack port 1 to switch 2/stack port 2, then switch 2/stack port 1 to switch 3/stack port 2 and so forth, with the bottom switch connecting to the top switch to complete the ring.

1. Connect one uplink for the entire switch stack. 
2. Power on all the switches, then waits several minutes for them to download the latest firmware and updates from Dashboard. The switches may reboot during this process.
   • The power LEDs on the front of each switch will blink during this process.
   • Once the switches are done downloading and installing the firmware, their power LEDs will stay solid white or green.
3. Navigate to Switch > Monitor > Switch stacks.
4. Configure the switch stack in Dashboard. If Dashboard has already detected the correct stack under Detected potential stacks, click Provision this stack to automatically configure the stack.
   Otherwise, to configure the stack manually:

• Navigate to Switch > Monitor > Switch stacks.
• Click add one / Add a stack:

[PhilipDAth · Accepted solution]

The original switch port configuration will be maintained (trunk, access, vlans, etc).

Things like layer 3 interfaces, spanning tree priority, etc will be wiped.  Things that you configure across the whole switch.

So in summary, port style config is kept, switch style config is lost.

[rhbirkelund]

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@alemabrahao wrote:
When a new switch stack is created, or a new switch is added to an existing stack, the below configurations will be removed from the stand-alone switch(es) and will need to be reconfigured on the stack:

• Link aggregates

[...]

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Hah! That explains the recent f*ck up on a customer network I made, when guiding the customer to stack two switches, resulting in a loop.

I honestly thought that it was the clean, unprovisioned switch introduced with redundant stack cables that made the loop, and brought everything down.