We are planning to upgrade from 6.0U3 to 6.5U1. The controllers in our vSAN clusters are SMC2308 cards running in pass-through mode. Unfortunately these controllers are not on the HCL for vSAN 6.6, so we will need to upgrade them. We are planning on going to Intel RS3UC080 controllers. My plan is to upgrade one of the controllers in a 5-node hybrid cluster first, and let that run for a while until we do the rest of them (13 total controllers in 3 different clusters).
A couple questions:
1. Is it ok to have different controllers in a cluster for a short while?
2. I'm thinking the best way to do this is to put the host in maintenance mode with full data migration, remove the disk groups, swap out the controller, and recreate the disk groups. But I'm curious what would happen if I just swap out the controller without migrating the data. Is it possible that the disk groups would remain on the new controller so that a full re-sync wont be necessary?
Any advice you can offer would be greatly appreciated.
Q1: Provided all controllers are certified for use with the version of vSAN you are using, this shouldn't cause any serious issues. Homogenous hardware is of course best practice and strongly advised, but mixed controllers should function normally during a (relatively) short maintenance period. Naturally, take good back-ups before any large maintenance job such as this in the event that anything should go awry.
Q2: Full evacuation and removal of the disk-groups is required when switching controllers to a different model, so unfortunately rolling-resync will be needed.