Need Switch Stacking Help

[pbiggs]

Hello

We recently purchased 4 Cisco Catalyst 9300x 48x UPOE+ switches to use in a switch stack configuration. I have made sure that the Stack Wise cables are all connected properly but when the switches boot up only 3 switches are found and are in the stack. I have tried renumbering the switches, removing them all and removing members, re connecting all the stack cables etc. but still the same issue. From what I understand we should be able to stack up to 9 switches. Is this not the case? 

[Jens Albrecht · Accepted solution]

Hello @pbiggs,

in case of the Cisco Catalyst 9300 Stackwise System up to a maximum of 8 switches can be stacked together physically in a ring topology. So running a stack of 4 switches should be no problem.

First of all, the switches have to meet a couple of prerequisites:

• Software version of all members must match.
• License level must match.
• Operational mode (Install vs Bundle) must match.

Regarding the cabling make sure that you properly close the stack ring.

Then verify the status with the following show commands:

• show switch detail (switch numbers and port status)
• show switch stack-ports summary (port status and cable details)
• show switch stack-ring speed (confirm that stack speeds match)

You can find more details in the following support document: Verify and Troubleshoot Stackwise on Catalyst 9200/9300.

Please post the output of the above commands in case you need further help.

HTH!

[pbiggs]

Hello and thank you for your help with this. I will definitely check these items tomorrow when I am back in the office. As I had mentioned these are all new switches out of the box. I did see that the IOS version running is 17.2 on each switch. As mentioned with their being directly out of box I am thinking they should be the same license version also. I will have to check the operational mode on them though. I have not even done any configuring on them. I just booted them up with all stack cables attached. I will post findings and thank you again for your help. 

[pbiggs]

So far on the troubled switch I found that the ring speed is wrong. The switches which are included in the stack have the following:

Switch#show switch stack-ring speed

Stack Ring Speed : 500G
Stack Ring Configuration: Half
Stack Ring Protocol : StackWise

The switch with the problem has

Switch#show switch stack-ring speed

Stack Ring Speed : 240G
Stack Ring Configuration: Down
Stack Ring Protocol : StackWise

They say to boot to ROMMON mode and edit the speed there which I have and the reload the switch. Doing this now and will let everyone you know if this was the fix. 

[Leo Laohoo]

conf t
 software auto-upgrade enable
end
wr

[pbiggs]

I wanted thank everyone for your help with this. This is our first switch stack and it seemed weird to just have an issue right out of the box. Anyway, Jens I followed your post closely and it ended up being the Stack Ring Speed : 240G. You have to boot into the ROMMON mode on the switch by repeatedly pressing the mode button on front of the switch. I am adding that because everything I looked for was saying to hold down the mode button or hit ctrl/break on the keyboard. Not so! With this model switch I needed just to press the mode button repeatedly during the switch boot up. Next I had to enter SWITCH_IGNORE_STARTUP_CFG=1 and then switch stack-speed 500. After this reload and it will ask to save. Once the switch came up the speed was set to 500 like the others in the stack and once I reconnected the cables (while the switches were down) they all came up as one switch stack. I hope this helps someone in the future that is wrestling with the same issue I had. Thank you all for your help again! 

[Jens Albrecht]

Hello @pbiggs,

first of all, I am glad that your stack is now working as expected. Feel free to ask any further questions you may have.

You can also change the stack-speed in global config mode, not only in rommon.
On the single switch it was set to 'low' for whatever reason and you can adjust this with the following commands:

Switch# configure terminal
Switch(config)# switch stack-speed high
Switch(config)# exit
Switch# copy run start
Switch# reload

A reload is mandatory in this case as well.

I also recommend the 'software auto-upgrade enable' command as mentioned by @Leo Laohoo.

It ensures software consistency across all stack members and makes your life much easier when doing software upgrades or adding new stack members.

HTH!

[pbiggs]

Thanks again Jens and everyone for their input as well. I ended following some document which advised to do it in ROMMON but if you can do in config mode its much easier. Thank you again! With the software auto-upgrade enable I was thinking it would need a connection out and these switches are currently on a table being set up. Once I do have a connection outbound would there be any issues with doing this and do you keep it enabled? 

[Jens Albrecht]

The auto-upgreade feature is supported when operating the stack in install mode and should always be enabled.

This is the recommended best practice to ensure ongoing firmware consistency. Simply turn it on and let it do its job.