Change vmkernel for VSAN on working vSAN Cluster

[Naumishe]

Hello community!

I need some advice!

I have vSAN cluster with 5 hosts. Each host has 2 vmkernels (each one in different PortGroup with different IP and different VLAN and 2 uplinks (active-standby)).

What will happen if I add new vmkernel (different dvswitch,different uplinks, ip and vlan) on one of my hosts and check checkbox VSAN for this vmkernel?

What will happen if I add such new vmkernel step by step on every host in cluster?

Traffic will start to walk on these uplinks after I add vmkernel on last host? Will I need to enter my hosts in maintenance mode for such operation?

And what will happen if I begin to disable old VSAN vmkernels step by step on my hosts?

[perthorn]

Hi Naumishe,

I haven't actually tried this so I don't know for sure, but I strongly suspect this will not work. Basically vSAN doesn't support utilizing multiple vmkernel ports, so you cannot be in a situation where one host is using 2 vmkernel ports for vSAN at the same time. I don't think anything at all will happen when you add a new vSAN enabled vmk to each hyp (if if even allows you), vSAN will just continue to use the old network. When you remove the first vSAN enabled vmk from a host, you are basically just removing a live vSAN vmk, the host would then disconnect from the vSAN cluser and you get a bunch of heath alerts.

Cheers

Per

[Naumishe]

Now I can see that hosts use both of vmkernels and both uplinks(each vmkernel connected with own uplink). When I run proactive tests I also see that this scheme use maximum from two uplinks.