To ensure the successful migration of the vCenter Server, vCenter Single Sign-On, and Platform Services Controller, you must preform some required tasks and pre-checks before running the migration.

Download and Mount the vCenter Server Appliance Installer.

Verify that the clocks of all machines on the vSphere network are synchronized. See Synchronizing Clocks on the vSphere Network.

Verify that your system meets the minimum software and hardware requirements. See System Requirements for the New vCenter Server Appliance and Platform Services Controller Appliance.

If you plan to deploy the new appliance on an ESXi host, verify that the target ESXi host is not in lockdown or maintenance mode.

If you plan to deploy the new appliance on an ESXi host, verify that the target ESXi host is not part of a fully automated DRS cluster.

If you plan to deploy the new appliance on a DRS cluster of the inventory of a vCenter Server instance, verify that the cluster contains at least one ESXi host that is not in lockdown or maintenance mode.

If you plan to deploy the new appliance on a DRS cluster of the inventory of a vCenter Server instance, verify that the cluster is not fully automated.

Verify that the source machine that you want to migrate does not run on an ESXi host that is part of a fully automated DRS cluster.

If you are migrating vCenter Server 5.5 and you have changed its host name, verify that the SSL certificate is configured correctly. For information about how to troubleshoot an error when you changed the vCenter Server 5.5 host name, see vSphere Troubleshooting in the VMware vSphere 5.5 Documentation.

Verify that you have sufficient disk space on the source machine that you want to migrate so that you can accommodate the data for the migration.

Back up the source machine that you want to migrate as a precaution in case of failure during the migration process.

If you use an external database, back up the external database.

If you plan to assign a static IP address in the temporary network settings of the appliance, verify that you have configured the forward and reverse DNS records for the IP address.

If you plan to assign a DHCP IP address in the temporary network settings of the new appliance, verify that the ESXi host on which you want to deploy the new appliance is in the same network as the ESXi host on which the existing vCenter Server Appliance runs.

If you plan to assign a DHCP IPv4 address in the temporary network settings of the new appliance, verify that the ESXi host on which you want to deploy the new appliance is connected to at least one network that is associated with a port group which accepts MAC address changes. Note that the default security policy of a distributed virtual switch is to reject MAC address changes. For information about how to configure the security policy for a switch or port group, see vSphere Networking.