V$BACKUP displays the backup status of all online datafiles.
FILE#
File identifier
STATUS
File status: NOT ACTIVE, ACTIVE (backup in progress), OFFLINE NORMAL, or description of an error. NOT ACTIVE indicates that the file is not currently in backup mode (that is, an ALTER TABLESPACE … BEGIN BACKUP or ALTER DATABASE BEGIN BACKUP statement has not been issued), whereas ACTIVE indicates that the file is currently in backup mode.
CHANGE#
System change number when backup started
TIME
Time the backup started
