/sys$common/syshlp/helplib.hlb RECOVER, Qualifiers, /FORWARD  *Conan The Librarian (sorry for the slow response - running on an old VAX)

    Rolls a file forward from a previous state. Use the /FORWARD
    qualifier to recover a backup file by using the after-image
    journaling information contained in a journal.

    You must always specify either /FORWARD or /BACKWARD, but you
    cannot specify both.

    When you use the /FORWARD qualifier, you must use a backup copy
    of the original data file as the file specification in your
    RECOVER/RMS_FILE command line.

    The re-doing operation starts at the time the most recent backup
    was made (assuming that the /RECORD qualifier was used), and the
    backup file is rolled forward until the time of the most recent
    entry in the journal. You can override the latter value with the
    /UNTIL qualifier.

    The file is rolled forward using the after-image journal that was
    specified when the file was marked for journaling with the SET
    FILE/AI_JOURNAL command. If the after-image journal has been
    moved from its original directory, or if it has a different
    file name, or if it has been restored to disk from magnetic
    tape, then you must use the /JOURNAL qualifier to identify the
    journal. If you have more than one journal (for example, if you
    did not use the BACKUP/RECORD command immediately after creating
    a new journal), then you must use a series of as many RECOVER
    /FORWARD commands as there are journals. The RMS Recovery Utility
    automatically knows which journal to use (unless it has been
    moved or restored from a backup copy, in which case you must
    use the /JOURNAL qualifier), and it also prompts you to issue
    a subsequent RECOVER/FORWARD command by displaying a message
    indicating that another journal is to be processed.

    When the after-image recovery operation is complete, you must re-
    mark the restored file for after-image journaling before it can
    be used for further processing using after-image journaling. Re-
    marking the file for after-image journaling sets the "journaling
    enabled" bit in the file header, which had automatically been
    turned off by the Backup Utility when the backup copy was made.
    Immediately after re-marking the restored file for after-image
    journaling, you should also make a backup copy of it.

    When you use after-image recovery for a file that also uses
    recovery unit journaling, the RMS Recovery Utility ensures
    that the data consistency provided by recovery unit journaling
    is maintained. The after-image journal includes records of a
    transaction being started, prepared, committed, or aborted.

    If you use the RECOVER/FORWARD command to roll forward a file
    (that is, the backup copy of a data file) that is also marked
    for recovery unit journaling, the file is rolled forward and
    includes modifications for all transactions that were completed
    (committed) on or before the ending time of the after-image
    recovery, as follows:

    o  If, at the time after-image recovery is to end, there are no
       active transactions, then after-image recovery takes place in
       the same way as when there is no recovery unit journaling.

    o  If one or more transactions are active at the time after-
       image recovery is to end, only those modifications made within
       transactions that were completed (committed) on or before the
       ending time are applied to the file.

       For example, suppose you issue the command RECOVER/FORWARD
       /UNTIL=10:30 for the backup copy of a file marked for both
       after-image and recovery unit journaling. When after-image
       recovery is complete, the restored file will include all
       modifications that were made within those transactions that
       completed on or before 10:30.

    o  If your application uses more than one file, the following
       conditions apply to the use of the /UNTIL qualifier:

       -  If you do not use the /UNTIL qualifier with the first
          backup copy that you restore with the RECOVER/FORWARD
          command, you need only restore those files in the
          application that are corrupted or lost. However, in this
          case, do not use the /UNTIL qualifier with any of the files
          that you restore, in order to maintain data consistency
          among all of those files.

       -  If you do use the /UNTIL qualifier with the first file
          that you restore with the RECOVER/FORWARD command, then
          you must restore every file in the application, and you
          must use the /UNTIL qualifier with the same time value for
          each file. If you do not use the same time value for the
          /UNTIL qualifier, then the modifications for one or more
          transactions may be restored to some of your files, but not
          to others.

          If you attempt to recover a file used in a multifile
          application that uses more than one after-image journal,
          the journals must be recovered in their entirety to assure
          transaction consistency. If you use the /UNTIL qualifier,
          the recovered files may still be inconsistent.