Disconnecting and Reconnecting a Host
You can disconnect and reconnect a host that is being managed by vCenter Server. Disconnecting a managed host does not remove it from vCenter Server; it temporarily suspends all monitoring activities performed by vCenter Server.
The managed host and its associated virtual machines remain in the vCenter Server inventory. By contrast, removing a managed host from vCenter Server removes the managed host and all its associated virtual machines from the vCenter Server inventory.
Understanding Managed Host Removal
Removing a managed host from vCenter Server breaks the connection and stops all monitoring and managing functions of that managed host and of all the virtual machines on that managed host. The managed host and its associated virtual machines are removed from the inventory. Historical data for removed hosts remains in the vCenter Server database.
The managed host and its associated virtual machines remain in the vCenter Server inventory. Removing a managed host from vCenter Server does not remove the virtual machines from the managed host or datastore. It removes only vCenter Server’s access to the managed host and virtual machines on that managed host.
If possible, remove managed hosts while they are connected. Removing a disconnected managed host does not remove the vCenter Server agent from the managed host. Make sure NFS mounts are active. If NFS mounts are unresponsive, the operation fails.
If you are removing a host which is part of a cluster, you must put the host into maintenance mode.
vCenter Server then returns the status of all associated processor and migration licenses to available