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

       /SHADOW=(device_name_1, device_name_2, device_name_3) label

    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.

    The INITIALIZE command with the /SHADOW and /ERASE qualifiers
    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 containing identical file structure information. All
       former contents of the disks are lost.

    You can then mount up to three of the devices that you have
    initialized in this way as members of a new host-based shadow
    set.

    Compaq strongly recommends that you use the /ERASE qualifier. By
    using the /ERASE qualifier, no merge operation is required when
    you create the shadow set with the MOUNT command.

    All the devices must have identical, nonzero values for Total
    Blocks. You can view the Total Blocks value by entering the
    SHOW DEVICE/FULL command. If a device has never been mounted
    or initialized on this system, the SHOW DEVICE/FULL command for
    the device will not display a value for Total Blocks. To correct
    this condition, either mount and then dismount the device,
    or initialize the device. The Total Blocks value will then be
    displayed by SHOW DEVICE/FULL.

    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.

    Additional information can be found in Volume Shadowing for
    OpenVMS.