Copyright Digital Equipment Corp. All rights reserved.
Qualifiers
/ABORT_VIRTUAL_UNIT
/ABORT_VIRTUAL_UNIT DSAnnnn: (Alpha/Integrity servers only)
Aborts mount verification on a shadow set.
Use this qualifier when you know that the unit cannot be
recovered. When you use this qualifier, the shadow set must be
in mount verification. The shadow set aborts mount verification
immediately on the node from which the command is issued. If the
shadow set is not in mount verification, this command returns the
error %SYSTEM-E-UNSUPPORTED, unsupported operation or function.
After this command completes, the shadow set still must be
dismounted. Use the following command to dismount the shadow
set:
$ DISMOUNT/ABORT DSAnnnn:
/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.
/COPY_SOURCE
/COPY_SOURCE {ddcu: | DSAnnnn:} (Alpha/Integrity servers only)
Specifies which source member of a shadow set will be used as
the source for read data during full copy operations when a third
member is added to the shadow set. This qualifier affects only
copy operations that do not use disk copy data (DCD) commands.
Some storage controllers, such as the HSG80, 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 lets you force all reads from a
single, specified source member for a copy operation.
If only a shadow set (DSAnnnn:) is specified, 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 shadow set member (ddcu:) is specified, 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.
/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.
/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.
/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.
/FORCE_REMOVAL
/FORCE_REMOVAL ddcu: (Alpha/Integrity servers only)
Expels the specified 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 specified device must be a member of a shadow set that is
mounted on the node where the command is issued.
/LOG
/LOG
/NOLOG (default)
Controls whether log information is displayed at the terminal.
/MEMBER_TIMEOUT
/MEMBER_TIMEOUT=n ddcu: (Alpha/Integrity servers only)
Specifies the timeout value to be used for a shadow set member.
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 16777215 seconds.
The specified device must be a member of a shadow set that is
mounted on the node where the command is issued.
/MV_INTVL
/MV_INTVL=n
Overrides the systemwide setting of the MVSUPMSG_INTVL system
parameter with the value specified by n (seconds) for the
specified device only. If /MV_INTVL=0, the value for MVSUPMSG_
INTVL is used instead. If MVSUPMSG_INTVL=0 or MVSUPMSG_NUM=0,
all mount verifications are announced. For more information about
MVSUPMSG_INTVL, see Sys_Parameters online help.
/MV_NUM
/MV_NUM=n
Overrides the systemwide setting of the MVSUPMSG_NUM system
parameter with the value specified by n (seconds) for the
specified device only. If /MV_NUM=0, the value for MVSUPMSG_NUM
is used instead. If MVSUPMSG_NUM=0 or MVSUPMSG_INTVL=0, all mount
verifications are announced. For more information about MVSUPMSG_
NUM, see Sys_Parameters online help.
/MVTIMEOUT
/MVTIMEOUT=n DSAnnnn: (Alpha/Integrity servers only)
Specifies the mount verification timeout value to be used for the
shadow set specified by its virtual unit name (DSAnnnn:).
The value supplied by this qualifier overrides the value
specified by the system parameter MVTIMEOUT for this specific
shadow set.
NOTE
You cannot change the value of MVTIMEOUT for a system disk.
Any attempt to do so results in an error.
The valid range for n is 1 to 16777215 seconds.
The specified shadow set must be mounted on the node where the
command is issued.
/PATH
/PATH=path-description-string
(For multipath devices only) Specifies a particular route to
the device. The path description string identifies a path from
the host to the device (for example, PGA0.2343-A855-BC99-876F or
PKC0.5). Wildcard characters have no special meaning. The path
description can be abbreviated to the minimum unique string.
Note that this qualifier does not imply that any action be
taken. To take action, you must also specify one of the following
qualifiers: /(NO)ENABLE, /(NO)POLL, or /SWITCH.
/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.
/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
DEVICE/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, see the VSI OpenVMS I/O User's Reference Manual.
/READ_COST
/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.
/RESET
/RESET=(keyword[,keyword])
Requires CMKRNL and DIAGNOSE privileges.
Resets either or both the error count and the operation count for
a device. You must specify one or both of the following keywords:
ERROR_COUNT Resets the error count.
OPERATION_ Resets the operation count.
COUNT
When either count is reset, a message is sent to the error log.
The message indicates that the count was reset and includes the
value of the counter before the reset.
/SITE
/SITE=n {DSAnnnn: | ddcu:} (Alpha/Integrity servers only)
Indicates to the shadowing driver the site location of the
specified shadow set (DSAnnnn:) or shadow set member (ddcu:). If
the member is removed from the shadow set and later is returned,
this qualifier must be specified again.
The SHADOW_SITE_ID system parameter defines the default site
location of the shadow set. You can override the default location
of the shadow set with the /SITE qualifier.
The valid range for the site location, represented by n, is 1
through 255.
After you apply this qualifier, the setting remains in effect
until you change it either with this command or with the SET
SHADOW/SITE command.
This qualifier can improve read performance because the member
that is physically local to the system will be the preferred disk
from which to read, provided that you specify the /SITE qualifier
for each shadow set member and for the shadow set. (In a Fibre
Channel configuration, shadow set members at different sites
are directly attached to the system. For the Volume Shadowing
and cluster software, there is no distinction between local and
remote in multiple-site Fibre Channel configurations.)
/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.
/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.
This command requires the OPER privilege. Additionally, if the
device is currently allocated by another process, as tape devices
often are, the SHARE privilege is needed.