VMS Help  —  INITIALIZE  Qualifiers  /SHADOW
       /SHADOW=(device_name_1, device_name_2, device_name_3) label
       (Alpha/Integrity servers only)

    Initializes multiple members of a future shadow set. Initializing
    multiple members in this way eliminates the requirement of a full
    copy when you later create a shadow set.

    When both the /SHADOW and /ERASE qualifiers are specified, the
    INITIALIZE command performs the following operations:

    o  Formats up to six devices with one command, so that any three
       can be subsequently mounted together as members of a new host-
       based shadow set

    o  Writes a label on each volume

    o  Deletes all information from the devices except for the system
       files and leaves each device with identical file structure
       information. All former contents of the disks are lost.

    HP strongly recommends that you use the /ERASE qualifier. When
    /ERASE is specified, a merge operation is substantially reduced.
    However, using /ERASE has two side effects that are important
    considerations for volume shadowing: the setting of the ERASE
    volume attribute and the time it takes to initialize a volume
    using /ERASE.

    If /ERASE is specified with /SHADOW, the disks are erased
    sequentially, which effectively doubles or triples the time
    it takes for the command to complete. If the disks are large,
    consider performing multiple, simultaneous INITIALIZE/ERASE
    commands (without /SHADOW) to erase the disks. Once all of
    those commands have completed, then execute an INITIALIZE/SHADOW
    command (without /ERASE).

    Once you have initialized your devices using /ERASE and /SHADOW,
    you can then mount up to three of these devices as members of a
    new host-based shadow set.

    Note that the INITIALIZE/SHADOW command should not be used to
    initialize a disk to be added to an existing shadow set, as no
    benefit is gained.

    For more information about volume shadowing, see the HP Volume
    Shadowing for OpenVMS manual.
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