Swapping stacking ports without blowing away config

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I've currently got 5 X450-G2's in a daisy chain stack (Bad I know) using the front 10GB ports. 

I've got the SFP passive cables for the "S1/2" ports on the back of the switch but I wanted to know if there's any easy way of swapping the stacking ports without having to rebuild the stack? 

# show stacking
Stack Topology is a Daisy-Chain
Active Topology is a Daisy-Chain
Node MAC Address    Slot  Stack State  Role     Flags
------------------  ----  -----------  -------  ---
*00:04:96:9a:26:e7  1     Active       Master   CA-
 00:04:96:99:ee:b3  2     Active       Standby  CA-
 00:04:96:9a:27:10  3     Active       Standby  CA-
 00:04:96:9a:26:e2  4     Active       Standby  CA-
 00:04:96:9a:27:80  5     Active       Standby  CA-
* - Indicates this node
Flags: (C) Candidate for this active topology, (A) Active Node

# show stacking-support 


Stack    Available Ports

Port    Native  Alternate  Configured  Current

-----   -----------------  ----------  ----------

1       Yes     51 *       Alternate   Alternate   

2       Yes     52 *       Alternate   Alternate   

stacking-support:          Enabled     N/A       


Flags: * - Current stack port selection


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Tom Taylor

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Posted 11 months ago

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Patrick Voss, Alum

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Hello Tom,

If you are just swapping a cable the stacking configuration will not be lost. This procedure would be easier in a ring topology because the blocked ports will become unblocked and all the nodes will remain up. Depending on which cable you are pulling it might be in your best interest to power down the nodes below that cable, make the swap and then power up each node one at a time.
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Tom Taylor

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I'll be swapping to a ring topology, will give it a go this weekend. Thanks for the advice 
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Patrick Voss, Alum

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In that case if the unused stacking ports are already configured then you should be able to just plug them in and everything will work.
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Tom Taylor

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Currently plugged in (I did it live a few days ago) and it didn't "swap". Prob just needs a reboot
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David Coglianese, Embassador

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Tom,

Reading your initial post it sounds like you want to go from front stacking using the 10G SFP+ ports to rear stacking using the QSFP+ ports. I believe Patrick and I are interpreting your question differently.

Can you please clarify which cables and ports you want to use going forward. I would think if you are going to switch to the rear ports you will need to configure stacking support to use the native ports at the very least. I do not know if you can do that on a switch that is already stacked.

Thanks,
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Tom Taylor

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That's exactly what I'm wanting to do :) move from the front stacking ports to the back
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David Coglianese, Embassador

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Thanks for the clarification. 

That is an interesting idea which is why I starting watch the thread. I would need to lab this up to know for sure how things will go.

But as I stated above you at least need makes changes to the stacking-support configuration and I don't think you can do that while they are stacked.

I think you will want to save the config as a script or as a session output or both. Blow it away with unconfigure switch all which I believe will default the stacking parameters to the native (rear) stack ports. You would then plug in the qsfp+ cables and configure stacking easy-setup.

Once the stack is rebuilt I believe you can dump the original config back onto the stack and be operational. You will then just need to configure ports 51 and 52 before you can use them as they wont have any config on them since they were stack ports in the original stack.

Again, I have not labbed this up, I will if I get a chance but am not sure if that will happen today.

Thanks,
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Tom Taylor

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That's what I was fearing, it's a pretty populated stack so was just looking for an easy-way-out approach. If it needs to be done then it needs to be done. 
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Patrick Voss, Alum

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I apologize, I did misread what you were attempting to do. David is right, you need to change the stacking-support configuration in order for this to work properly. Good news is that having this in a daisy chain might make this a little easier to perform.

Making a stacking-support configuration change can be done on an active stack but it requires a reboot of the specific node. You can also mix alternate and native stacking configuration. Since this is a daisy chain you can change the stacking configuration on the unused port to native on both switches, reboot and then connect the stacking cable. It should come up. Then rinse and repeat for the rest ports one link at a time. It may take a while but it will ensure the configuration and the stack remain up and stable.

I will see if I can mock this up in the lab and let you know how it goes.
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In theory you should be able to change them all at once, power them down, connect up the native stacking cables and power them up one by one. This is not something we see a ton so it hasn't really been tested.