I went through this a couple of years ago, found it in my notes, and thought I would share. We experienced a SAN outage that corrupted the vCSA 5.5 appliance internal database.
The symptoms that we had something bad happening in the vCenter where the following: The thick client wouldn’t always connect, and if it did you could only stay connected for a maximum of 5 minutes before getting kicked back to the login screen. The web client was acting very similar. We opened a Support request, and after looking at the logs we could see that there was corruption in one of the tables. Given that we were already going to upgrade this appliance anyway, VMware had suggested a hard cut-over, where we would backup the DVSwitch config, disconnect the hosts from the old 5.5 vCSA with the virtual machines still running, power down the old vCSA appliance, power on the new 6.0u1 vCSA, and re-attach the hosts to it. Sounds easy enough right?
The following is a high level view of the steps required to cut over to a new vCenter. This process assumes that traditional methods of upgrading to a new vCenter version cannot be trusted, and that standing up a new vCenter, and reconnecting the hosts to it, is the only viable option.
If the vCenter Appliance is in a bad state, it is always recommended to contact VMware GSS first and open an SR, to properly determine what is wrong, and what the best recovery options are. These steps were recorded on a 5.5 vCSA and 6.0u1 vCSA. Your mileage may very.
-=Process on the old vCenter Appliance=-
– Log in as the local Administrator
– Export DVSwitch config
– Create a standard switch mimicking distributed switch on first host
– Migrate one physical host nic (pnic) to the standard switch
– Update networking on all virtual machines on host over to the standard switch
– Migrate other host pnics to standard switch
– Disabled HA and DRS for the cluster
– Disconnected host from the vCenter
**Rinse wash repeat on remaining hosts until all are disconnected**
– Shutdown old vCenter Appliance.
-=Process on the new vCenter Appliance=-
– Startup the new vCenter Appliance and configure it.
– Log in as local Administrator
– Setup the data center and host clusters
– Add all hosts to the new vCenter
– Import DVSwitch config
– Add DVSwitch to hosts,
– Migrate one pnic on the host to DVSwitch
– Updated all VMs networking to DVSwitch
– Migrate other pnic to DVSwitch
**Rinse wash repeat on remaining hosts and VMs until they are on the DVSwitch**
– Disconnect standard switch from hosts