/READ_COST=n {ddcu: | DSAnnnn:} (Alpha/Integrity servers only)

    Enables you to modify the default cost assigned to each shadow
    set member (ddcu:). By modifying the assignments, you can bias
    the reads in favor of one member of a two-member shadow set,
    or, in the case of three-member shadow sets, in favor of one or
    two members of the set over the remaining members. The device
    specified must be a shadow set or member of a shadow set that is
    mounted on the node where the command is issued.

    The valid range for the specified cost is 1 to 65,535 units.

    The shadowing driver assigns default READ_COST values to shadow
    set members when each member is initially mounted. The default
    value depends on the device type and its configuration relative
    to the system mounting it. The following list of device types
    is ordered by the default READ_COST assignments, from the lowest
    cost to the highest cost:

    o  DECram device

    o  Directly connected device in the same physical location

    o  Directly connected device in a remote location

    o  DECram served device

    o  Default value for other served devices

    The value supplied by the /READ_COST qualifier overrides the
    default assignment. The shadowing driver adds the value of the
    current queue depth of the shadow set member to the READ_COST
    value and then reads from the member with the lowest value.

    Different systems in the cluster can assign different costs to
    each shadow set member.

    When this qualifier specifies a shadow set (DSAnnnn:) instead
    of a shadow set member, the /READ_COST qualifier switches the
    read cost setting for all shadow set members back to the default
    read cost settings established automatically by the shadowing
    software. The specified shadow set must be mounted on the node
    where the command is issued. In this case, the value specified
    for the cost can be any number because it will be ignored.

    If the /SITE command qualifier has been specified, the shadowing
    driver takes site values into account when it assigns default
    READ_COST values. In order for the shadowing software to
    determine whether a device is in the category of "directly
    connected device in a remote location," the /SITE command
    qualifier must have been applied to both the shadow set and the
    shadow set member.

    Reads requested for a shadow set from a system at site 1 are
    performed from a shadow set member that is also at site 1. Reads
    requested for the same shadow set from site 2 can read from the
    member located at site 2.