Question about stack beetween two 3850

[mulbreizh]

Hello and sorry for my bad english 

We have 2 cisco WS-C3850-48XS connect by stackwise, just one link by fiber.

We want to add second link between the 2 switchs. I see Cisco doc, it is possible, 4 link is possible.

So before connect the new fiber, we configure the ports on the switches by command : stackwise-virtual dual-active-detection

after pass this command, we receive : WARNING: All the extraneous configurations will be removed for TenGigabitEthernet1/0/43 on reboot.

But it is not clear, i can connect the fiber without reboot or i need to reboot for it works ?

Because if i need to reboot, i have to stop all the production, around 100 servers.

what do you thinks ?

thanks

[balaji.bandi]

Once stackwise virtual build, you need to reload the device for adding links or break the SVL and add and join back or other option force switch over and add the config.

if the Servers are dual homed force switchover should not cause the issue or breaking SVL should not cause the issue.

https://www.cisco.com/c/dam/en/us/products/collateral/switches/catalyst-3850-series-switches/q-and-a-c67-738577.pdf

some reference document :

https://www.cisco.com/c/en/us/td/docs/switches/lan/catalyst3850/software/release/16-9/configuration_guide/stck_mgr_ha/b_169_stck_mgr_ha_3850/configuring_cisco_stackwise_virtual.html

Why only SVL, Cat 3800 can be stacked physically (i would use this option).

[mulbreizh]

but ont this two 3850 stackwise is already configure, the second link is again between the same switches. So you sure we need to reload ?

[Georg Pauwen]

Helo,

I somewhere recall that you can use the command " redundancy force-switchover" to add a second link, and that will not require a full reload of the entire stack. When you use that command, there will be no outage either.

[balaji.bandi]

Once SVL build you can change the config, so i have provided differnet option how you can do :

Once stackwise virtual build, you need to reload the device for adding links or break the SVL and add and join back or other option force switch over and add the config.