Nexus Switch Migration - vPC

[Nathan Farrar]

I am planning a migration from pair of 5548 switches to a pair of 5672 switches. They are running vPC, FCoE, EIGRP, and various other services. My main concern is the storage aspect of things. There are a lot of VMs and storage arrays connected to 2Ks that are hanging off of the current 5548 switches. I don't think it is going to be feasible for them to shutdown all storage and machines in the time window provided. Can I migrate over to the new switches one at a time? I'm thinking I can bring down one side, the secondary of the vPC peering, and install the new secondary. Once that is up and all looks healthy I can do the same on the primary. I'm not seeing why this wouldn't work but I've never tried this before. I'd have to disable CFS to ensure that the two mismatched switches don't try to sync configurations. I figure that as long as my configurations on both sides match, the vPC peer link should come back up and traffic should flip over.

Thoughts? Anyone done this before?

Thanks!

[nazimkha]

vPC and port-channel across 2 different switch models would not work. I would bring up the nexus 5672 in vPC have them connected to the nexus 5548 and plan the server migration in a phased approach. Would decommission the nexus 5548 once all appliances servers have been migrated off to the new switch pair.

[Nathan Farrar · Accepted solution]

I'm happy to report that this does actually work! As long as your NX-OS versions are similar enough. I had them the same to prevent an image upgrade to the FEXs. I migrated all FCoE interfaces from one switch that was acting as fabric A, they failed over to B. I connected the keepalive and peer links for the VPC to the new switch. Brought it online and monitored the VPC link and saw that it came up without issue. Moved all connections to the replacement switch and performed the same on the secondary switch. No errors and no loss in storage traffic. The FEXs were a bit trickier, nothing was dual homed to both of the FEXs so I just switched connections over and brought up the new ones.

Once I had both new switches connected together, they continued their VPC relationship and HSRP took care of the L2 spoofing.