OptionalbackupBackupMsg resturns any relevant information like failure reason unfreeze failed etc...
OptionalbackupBackupName is the name of the executed backup
OptionalcheckpointCheckpointName is the name of the checkpoint created for the backup
OptionalcompletedCompleted indicates the backup completed
OptionalendEndTimestamp is the timestamp when the backup ended
OptionalfailedFailed indicates that the backup failed
OptionalstartStartTimestamp is the timestamp when the backup started
OptionalvolumesVolumes lists the volumes included in the backup
VirtualMachineInstanceBackupStatus tracks the information of the executed backup