This really depends on what your goal for the backup is? If you are just trying to protect against end user errors, such as deleted data within the vdb, then backup is simply taking a snapshot and restoring is performing a rewind or provisioning that snapshot to a new vdb.
If you want to protect against failure for the entire Delphix Engine, then you have a few options, primarily performing vmware level backups or engine replication. Our documenting covers these options -
Backup and Recovery Strategies for the Delphix Engine