About VMware discovery
NetBackup automatically starts the discovery of the VMware server when you add a VMware server or update credentials. The backup host information is used to validate the credentials and perform the discovery.
To serve as a backup host, a media server or client must be at NetBackup 8.1.2 or later. For older versions, the backup host credential validation succeeds, but the discovery of the VMware servers fails. Discovery occurs at set intervals. (The default interval is every 8 hours.)
See Change the autodiscovery frequency of VMware assets.
To discover the VMs immediately: