I use a vcsa6. It crashed, lost his database and rebooted in an empty vCenter..
I had a DVSwitch and all hosts were connected.
So I added the cluster and re-added the hosts. They still work but on the old, not-existing anymore DVSwitch.
Is there a way to recreate the same DVSwitch?
What would be the procedure to make the change everything to the new one?
I added the host to the new one and they see it. But when I change the physical NIC to the new one, I lose the host connection and it rolls back.
Rollback happens because your host detects that you have implemented a networking change that disconnects the host from vCenter. This is enabled by default. (can be disabled with vcenter adv setting config.vpxd.network.rollback, however don't touch it for now. it is there for a reason)
You pretty much will have to re-create the new dvSwitch config from scratch, connect all your hosts to the new dvSwitch and then migrate physical nics, VMs and vmkernel ports to the new one.
Now whether this will involve downtime / connectivity loss depends heavily on your existing ghost-switch configuration.
From symptoms you describe it sounds like original switch was not really set up to tolerate pNIC loss therefore most likely you will have some downtime / net connectivity loss during migration.
To avoid rollback and host-to-vcenter connectivity loss you can and should move the pNIC and your management vmkernel port at the same time. If the new dvSwitch is set up correctly, this should work.
1) Right click on your new dvswitch and select "Add and Manage Hosts"
2) select "Manage Host Networking"
3) Select the host you're working on
4) tick "manage physical adapters" and "manage vmkernel adapters"
5) select the physical adapter you want to connect to uplink port on your new dvSwitch and click on "Assign uplink"
6) select your existing vmkernel port used for management (now connected to your ghost switch), click on "Assign port group" and choose the portgroup you have created on your new dvswitch for management traffic
next - next - finish and observe your changes. If all good, move the remaining physical adapters, vmkernel ports and virtual machines on that host to your new dvswitch.
then repeat this for all your other affected hosts.
once you are sure that everything is working just fine, right click on your new dvswitch - settings - export configuration
hope this helps