That is correct. Using swing ESXi is one of the prefered method for migration. Another option is shared DataStore (iSCSI/NFS) import the VM browsing the data store and storage vMotion them to the vSAN
I am in the planning stage for migrating from a vSphere 6.0 cluster to a VxRail cluster which will be using using Internal VCSA with external PSC inlcuded (PSC that comes with the embedded VCSA). I have understood that there is no way to add a standalone ESXi host to the internal VCSA that comes with VxRail and do vMotion from the Standalone Host to the new cluster. What I wonder is if it is possible to join the old vCenter to the PSC which will be deployed in VxRail or is it limited in some manner like the embedded VCSA?  Has anyone faced the same issue and did you find a reasonable solution to live migrate virtual machines between an old vCenter into the embedded one?  2 Other options seem to be doing scripted migration using vSphere Power CLI or using VMware converter but this seem to be a bit troublesome in comparison.  Any suggestions are greatly appreciated.  Thanks
Join External vCenter to VxRail PSC