VMS Help SET, DEVICE, Qualifiers  *Conan The Librarian (sorry for the slow response - running on an old VAX)

1 - /AVAILABLE

       /AVAILABLE
       /NOAVAILABLE

    Controls whether the specified disk or magnetic tape is to be
    considered available. You must dismount the specified disk
    or magnetic tape before entering the SET DEVICE/[NO]AVAILABLE
    command. If you specify the /NOAVAILABLE qualifier, any attempt
    to allocate or mount the specified disk or magnetic tape is
    prevented. Devices are automatically set /AVAILABLE when brought
    online even if the device had been previously set /NOAVAILABLE.

2 - /ABORT_VIRTUAL_UNIT

       /ABORT_VIRTUAL_UNIT DSAnnnn:

    Aborts mount verification.

    To use this qualifier, the shadow set must be in mount
    verification. When you specify this qualifier, the shadow set
    aborts mount verification immediately on the node from which the
    qualifier is issued. Use this qualifier when it is known that the
    unit cannot be recovered.

    Note that after this command completes, the shadow set must still
    be dismounted. Use the following command to dismount the shadow
    set:

    $ DISMOUNT/ABORT DSAnnnn:

3 - /COPY_SOURCE

       /COPY_SOURCE (ddcu:,DSAnnnn:)

    Controls whether one or both source members of a shadow set are
    used as the source for read data during full copy operations,
    when a third member is added to the shadow set. This only affects
    copy operations that do not use DCD operations.

    HSG80 controllers have a read-ahead cache, which significantly
    improves single-disk read performance. Copy operations normally
    alternate reads between the two source members, which effectively
    nullifies the benefits of the read-ahead cache.

    This qualifier allows you to force all reads from a single source
    member for a copy operation.

    If the shadow set is specified, then all reads for full copy
    operations will be performed from the disk that is the current
    "master" member, regardless of physical location of the disk.

    If a member of the shadow set is specified, then that member will
    be used as the source of all copy operations. This allows you to
    choose a local source member, rather than a remote master member.

4 - /DUAL_PORT

       /DUAL_PORT
       /NODUAL_PORT

    Controls whether the port seize logic in the device driver of
    the specified disk is to be enabled. This qualifier should be
    used only on disks that contain a dual port kit and have been
    dismounted.

5 - /ENABLE

       /ENABLE
       /NOENABLE

    Enables or disables a path to a multipath device; the affected
    path is the one named in the /PATH qualifier. All paths are
    initially enabled; the current path cannot be disabled.

6 - /ERROR_LOGGING

       /ERROR_LOGGING
       /NOERROR_LOGGING

    Controls whether device errors are logged in the error log file.
    When you specify the /ERROR_LOGGING qualifier, all error messages
    reported by the device on which error logging is enabled are
    recorded in the error log file. Use the SHOW DEVICE/FULL command
    to find out the current status.

7 - /FORCE_REMOVAL

       /FORCE_REMOVAL ddcu:

    Expels a named shadow set member from the shadow set.

    If connectivity to a device has been lost and the shadow set is
    in mount verification, this qualifier causes the member to be
    expelled from the shadow set immediately.

    If the shadow set is not currently in mount verification, no
    immediate action is taken. If connectivity to a device has
    been lost but the shadow set is not in mount verification, this
    qualifier lets you flag the member to be expelled from the shadow
    set, as soon as it does enter mount verification.

    The device specified must be a member of a shadow set that is
    mounted on the node where the command is issued.

8 - /LOG

       /LOG
       /NOLOG (default)

    Controls whether log information is displayed at the terminal.

9 - /MEMBER_TIMEOUT

       /MEMBER_TIMEOUT=n ddcu:

    Specifies the timeout value to be used for a member of a shadow
    set.

    The value supplied by this qualifier overrides the system
    parameter, SHADOW_MBR_TMO, for this specific device. Each member
    of a shadow set can be assigned a different MEMBER_TIMEOUT value.

    The valid range for n is 1 to 16,777,215 seconds.

    The device specified must be a member of a shadow set that is
    mounted on the node where the command is issued.

10 - /MVTIMEOUT

       /MVTIMEOUT=n DSAnnnn:

    Specifies the mount verification timeout value to be used for
    this shadow set, specified by its virtual unit name, DSAnnnn:.

    The value supplied by this qualifier overrides the system
    parameter, MVTIMEOUT, for this specific shadow set.

    The valid range for n is 1 to 16,777,215 seconds.

    The device specified must be a shadow set that is mounted on the
    node where the command is issued.

11 - /PATH

       /PATH=path-description-string

    Specifies a particular route to the device. The path description
    string identifies a path from the host to the device (for
    example, PKA0.2343-A855-BC99-876F or PKC0.5). Wildcard characters
    have no special meaning. The path description may be abbreviated
    to the minimum unique string.

    This qualifier applies only to multipath devices.

12 - /POLL

       /POLL
       /NOPOLL

    Specifies that the path specified by the /PATH qualifier is to be
    polled for continued availability as a path switch destination.
    This does not affect any attempt to switch to this path. Its
    purpose is only to inform an operator that a path may or may not
    be viable as a path switch destination. By default, all device
    paths are enabled for polling when they are discovered. Note that
    this qualifier applies only to multipath devices.

13 - /PREFERRED_CPUS

       /PREFERRED_CPUS=cpu-a[,cpu-b,cpu-c,...]
       /NOPREFERRED_CPUS

    Allows you to specify a CPU or a set of candidate CPUs from
    which the operating system chooses the CPU to assign to the Fast
    Path port. The chosen CPU is called the preferred CPU for this
    Fast Path port. The Fast Path port's interrupt I/O completion
    processing and I/O initiation processing are performed on this
    preferred CPU.

    In addition to selecting the preferred CPU, the User Preferred
    CPU is set for this port. Setting the User Preferred CPU prevents
    the port from being reassigned to another CPU unless the User
    preferred CPU is being stopped. The qualifier can be negated.
    When the /NOPREFERRED_CPUS qualifier is specified, the User
    Preferred CPU is cleared for the port, but it remains a Fast
    Path port, and the current preferred CPU is not changed.

    If both /PREFERRED_CPUS and /NOPREFERRED_CPUS are specified on
    the same command line, /NOPREFERRED_CPUS is ignored.

    If Fast Path is enabled, you can use the DCL command, SHOW
    DEVICES/FULL, to display the current preferred CPU and the User
    Preferred CPU.

    For more information about using Fast Path features to improve
    I/O performance, refer to the OpenVMS I/O User's Reference
    Manual.

14 - /READ_COST

       /READ_COST=n ddcu:

    Allows you to modify the default "cost" assigned to each member
    of a shadow set, so that reads are biased or prioritized toward
    one member versus another.

    The valid range for n is 1 to 65,535 units.

    The device specified must be a member of a shadow set that is
    mounted on the node where the command is issued.

    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. There are default values for a
    DECRAM device; a directly connected device in the same physical
    location; a directly connected device in a remote location;
    a DECram served device; and a default value for other served
    devices.

    The value supplied by this 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.

    If the /SITE command qualifier has been specified, the shadowing
    driver will take site values into account when it assigns default
    READ_COST values. Note that 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
    individual device.

    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.

15 - /READ_COST

       /READ_COST=n DSAnnnn:

    Switches the read cost setting for all shadow set members back to
    the default read cost settings established automatically by the
    shadowing software. DSAnnnn: must be a shadow set that is mounted
    on the node from which this command is issued.

    The valid range for n is any nonzero number. The value supplied
    has no inherent meaning.

16 - /SITE

       /SITE=(n, logical_name) (ddcu: DSAnnnn:)

    Indicates to the shadowing driver the site location of the shadow
    set member or of the shadow set (represented by its virtual unit
    name). Prior to using this qualifier, you can define the site
    location in the SYLOGICALS.COM command procedure to simplify its
    use.

    The valid range for the site location designator, n, is 1 through
    255.

    The following example shows the site locations defined, followed
    by the use of the /SITE qualifier:

    $ DEFINE/SYSTEM/EXEC ZKO 1
    $ DEFINE/SYSTEM/EXEC LKG 2
    $!
    $! At the ZKO site ...
    $ MOUNT/SYSTEM DSA0/SHAD=($1$DGA0:,$1$DGA1:) TEST
    $ SET DEVICE/SITE=ZKO  DSA0:
    $!
    $! At the LKG site ...
    $ MOUNT/SYSTEM DSA0/SHAD=($1$DGA0,$1$DGA1) TEST
    $ SET DEVICE/SITE=LKG  DSA0:
    $!
    $! At both sites, the following would be used:
    $ SET DEVICE/SITE=ZKO  $1$DGA0:
    $ SET DEVICE/SITE=LKG  $1$DGA1:

17 - /SPOOLED

       /SPOOLED[=(queue-name[:],intermediate-disk-name[:])]
       /NOSPOOLED

    Controls whether files are spooled to an intermediate disk.

    The queue name indicates the printer queue to which a file is
    queued. If a queue name is not supplied, the default is the name
    of either the printer or terminal.

    The intermediate disk name identifies the disk to which the
    spooled files are written. If the intermediate disk name is not
    supplied, the default is SYS$DISK (the current default disk). The
    intermediate disk must be mounted before files can be written to
    it.

    Once the device has been set spooled to a disk, that disk cannot
    be dismounted until the spooled device is set to /NOSPOOLED.
    All channels must be deassigned from a print device before its
    spooling characteristics can be changed. Also, the queue that is
    assigned to the device must be stopped.

18 - /SWITCH

    Attempts to switch from the current path of a multipath device
    to the path named in the /PATH qualifier. The path switch
    is attempted only if the path has not been disabled by SET
    DEVICE/NOENABLE. The path switch is initiated but not completed
    before returning control to the user; use SHOW DEVICE/MULTIPATH
    to verify that the path switching has completed successfully.