Checksum_Verification
    Nochecksum_Verification

    The Checksum_Verification qualifier requests that the RMU Backup
    command verify the checksum stored on each database page before
    the backup operation is applied, thereby providing end-to-end
    error detection on the database I/O. The default value is
    Checksum_Verification.

    Oracle Corporation recommends that you accept this default
    behavior for your applications. The default behavior prevents
    you from including corrupt database pages in backup files
    and optimized .aij files. Without the checksum verifications,
    corrupt data pages in these files are not detected when the files
    are restored. The corruptions on the restored page may not be
    detected until weeks or months after the backup file is created,
    or it is possible the corruption may not be detected at all.

    The Checksum_Verification qualifier uses additional CPU resources
    but provides an extra measure of confidence in the quality of the
    data that is backed up.

    Note that if you specify the Nochecksum qualifier, and undetected
    corruptions exist in your database, the corruptions are included
    in your backup file and are restored when you restore the backup
    file. Such a corruption might be difficult to recover from,
    especially if it is not detected until long after the restore
    operation is performed.