HELPLIB.HLB  —  SET  VOLUME
    Changes the characteristics of one or more mounted Files-11
    volumes. The SET VOLUME command affects only the node on which
    the command is issued, and will not affect any other nodes, even
    when a volume is mounted on multiple nodes in an OpenVMS Cluster
    configuration.

    If you are not the owner of the volume, requires control access
    to the volume.

    Format

      SET VOLUME  device-name[:][,...]

1  –  Parameter

 device-name[:][,...]

    Specifies the name of one or more mounted Files-11 volumes.

2  –  Qualifiers

2.1    /ACCESSED

       /ACCESSED[=n]

    Requires OPER (operator) privilege.

    Specifies the number of directories to be maintained in system
    space for ready access. You can specify a value n in the range
    of 0 to 255. If you specify the qualifier /ACCESSED and omit
    the number of directories, a default value of 3 is used. If you
    specify a value greater than the current value, the new value is
    effective immediately; otherwise, the new value is not effective
    until the next time the volume is mounted.

2.2    /CACHE

       /CACHE=(option[,...])

    Enables or disables XFC caching for the volume. If CLEAR_DATA
    option is specified, then contents of the volume already in cache
    are cleared. (If you do not specify the /CACHE qualifier, XFC
    caching attributes of the volume as well as the contents of
    the volume already in cache are not affected.) Keywords are as
    follows:

    Keyword     Description

    DATA        Enables XFC caching for the volume.
    [NO]DATA    Disables XFC caching for the volume.
    CLEAR_DATA  Clears contents of the volume present in the XFC
                cache (if any).

2.3    /DATA_CHECK

       /DATA_CHECK[=(option[,...])]

    Defines a default for data check operations following all read
    and write operations to the specified volume. (If you do not
    specify the /DATA_CHECK qualifier, no checks are made.) Keywords
    are as follows:

    [NO]READPerforms checks following all read operations.
    [NO]WRITPerforms checks following all write operations (default).

2.4    /ERASE_ON_DELETE

       /ERASE_ON_DELETE
       /NOERASE_ON_DELETE (default)

    Determines whether the space occupied by a file is overwritten
    with a system-specified pattern when a file on the volume is
    deleted.

2.5    /EXTENSION

       /EXTENSION[=n]

    Specifies the number of blocks to be used as a default extension
    size for all files on the volume. You can specify a value n in
    the range of 0 to 65,535. If you specify the /EXTENSION qualifier
    without specifying a value, a default value of 0 (the OpenVMS RMS
    default) is used.

    For example, during an update operation, the extension default
    is used when a file increases to a size greater than its initial
    default allocation.

2.6    /FILE_PROTECTION

       /FILE_PROTECTION=(ownership[:access][,...])

    Sets the default protection to be applied to all files on the
    specified disk volume. Specify the ownership parameter as system
    (S), owner (O), group (G), or world (W) and the access parameter
    as read (R), write (W), execute (E), or delete (D). A null access
    specification means no access.

                                   NOTE

       This attribute is not used while the volume is in use on an
       OpenVMS system, but the attribute is provided to control
       the process use of the volume on RSX-11M systems. The
       OpenVMS system always uses the default file protection;
       the protection can be changed with the DCL command SET
       PROTECTION/DEFAULT.

2.7    /HIGHWATER_MARKING

       /HIGHWATER_MARKING
       /NOHIGHWATER_MARKING

    Determines whether the file highwater mark (FHM) volume attribute
    is set. The FHM attribute guarantees that a user cannot read data
    that was not written by the user. Applies to Files-11 On-Disk
    Structure Level 2 (ODS-2) and 5 (ODS-5) volumes only.

2.8    /LABEL

       /LABEL=volume-label

    Specifies a 1- to 12-character ANSI name to be encoded on the
    volume. The specified label remains in effect until it is changed
    explicitly; dismounting the volume does not affect the label. VSI
    strongly recommends that a volume label should consist of only
    alphanumeric characters, dollar signs ($),  underscores (_), and
    hyphens (-).

                                   NOTE

       Changing the volume label does not change other structures
       that used the original volume label. For example, the
       DISK$label logical volume name is not changed nor is the
       device-lock name that is kept internally by OpenVMS. As a
       result, if you attempt to access another disk that has the
       same volume label as the original volume of this device,
       you may get error messages such as the following: "%MOUNT-F-
       VOLALRMNT, another volume of same label already mounted".

       VSI recommends that, if you change a disk volume label,
       you also dismount and remount the disk on all nodes in the
       cluster so that the names and locks are consistent.

    If you change the volume label on a nonsystem disk and the
    PRODUCT INSTALL command has been used to install software
    products on that disk, you must update the software product
    database to reflect this change. To accomplish this, first
    dismount and remount the disk. Then use the PRODUCT REGISTER
    VOLUME command to replace all occurrences of the old DISK$label
    with the new logical volume name that was created by the MOUNT
    command.

                                   NOTE

       You do not need to take this action when you change
       the label of the system disk. The POLYCENTER Software
       Installation Utility continues to use the old logical
       volume name until the system is rebooted. After reboot (when
       the system disk is remounted), the utility automatically
       identifies the system disk using its new logical volume
       name.

2.9    /LIMIT

       /LIMIT[=n]

    Specifies that the volume is to be enabled for volume expansion.
    n specifies the upper limit of the expansion (in blocks). If no
    value is specified, the maximum expansion potential is set up.

    The maximum expansion size depends on the cluster size defined
    for the volume using the INITIALIZE/CLUSTER_SIZE command. If
    the cluster size is 8 or more, the current maximum expansion
    supported on OpenVMS (1TB) is set up. If the cluster size is less
    than 8, the expansion limit is set to 65535*4096*Cluster-size
    because the maximum size of the bitmap is 65535 blocks. For more
    information about volume expansion, see the VSI Volume Shadowing
    for OpenVMS manual.

    This command must be executed while the disk is mounted
    privately.

    If you add additional physical storage in the future, you can use
    the /SIZE qualifier to increase the volume size.

2.10    /LOG

       /LOG
       /NOLOG (default)

    Determines whether the volume specification of each volume is
    displayed after the modification.

2.11    /MOUNT_VERIFICATION

       /MOUNT_VERIFICATION
       /NOMOUNT_VERIFICATION

    Determines whether mount verification is enabled. Mount
    verification prevents interruption to user input/output
    operations and notifies the operator of problems with the disk.

2.12    /OWNER_UIC

       /OWNER_UIC[=uic]

    Sets the owner user identification code (UIC) of the volume
    to the specified UIC. The default UIC is that of the current
    process. Brackets ([])  are required around the UIC. Specify the
    UIC by using standard UIC format as described in the VSI OpenVMS
    Guide to System Security.

2.13    /PROTECTION

       /PROTECTION=(ownership[:access][,...])

    Specifies the protection to be applied to the volume. The
    following rules apply:

    o  Specify the ownership parameter as system (S),  owner (O),
       group (G),  or world (W).

    o  Specify the access parameter as read (R),  write (W), create
       (C),  or delete (D).

    The default protection is all types of access by all categories
    of user.

2.14    /REBUILD

       /REBUILD[=FORCE]

    Recovers caching limits for a volume that was dismounted
    improperly. If a disk volume was dismounted improperly (such
    as during a system failure), and was then remounted with the
    MOUNT/NOREBUILD command, you can use SET VOLUME/REBUILD to
    recover the caching that was in effect at the time of the
    dismount. The FORCE option forces the disk to be rebuilt
    unconditionally, thus updating the free block count in the disk
    volume's lock value block.

2.15    /RETENTION

       /RETENTION=(min[,max])

    Specifies the minimum and maximum retention times to be used by
    the file system to determine the expiration date for files on
    the volume. When a file is created, its expiration date is set
    to the current time plus the maximum time. Each time the file is
    accessed, the current time is added to the minimum time. If the
    sum is greater than the expiration date, a new expiration date is
    computed.

    If you omit the maximum value, a default value that
    is the smaller of (2 x min) or (min + 7) days is
    used. For example, /RETENTION=3- is the same as
    /RETENTION=(3-,6-), while /RETENTION=10- is the same as
    /RETENTION=(10-,17-).

    The command SET VOLUME/RETENTION=0 disables retention times on
    the volume.

2.16    /SIZE

       /SIZE[=nnn]

    Specifies the amount of disk space (in blocks) that is usable for
    the file system. This value must be greater than the current
    logical volume size and less than or equal to the physical
    size of the disk or the expansion limit (specified by /LIMIT),
    whichever is smaller.

    If the value is omitted, the usable space is increased to the
    physical size of the disk or the expansion limit, whichever is
    smaller.

2.17    /STRUCTURE_LEVEL

       /STRUCTURE_LEVEL=n

    Sets the structure level of the volume. Use the value 5 to set
    the volume to ODS-5.

    When the /STRUCTURE_LEVEL qualifier is used with other
    qualifiers, the volume structure level is set prior to the other
    qualifiers being performed.

    You cannot use the SET VOLUME command to change a volume from
    ODS-5 to ODS-2. To reset a volume to ODS-2, see the instructions
    in the VSI OpenVMS System Manager's Manual, Volume 1: Essentials.

2.18    /SUBSYSTEM

       /SUBSYSTEM
       /NOSUBSYSTEM

    Enables the processing of subsystem ACEs. Requires the SECURITY
    privilege. By default, the disk from which you boot has protected
    subsystems enabled but other disks do not. For further details on
    subsystems, see the VSI OpenVMS Guide to System Security.

2.19    /UNLOAD

       /UNLOAD (default)
       /NOUNLOAD

    Specifies whether the volume is unloaded (spun down) when the DCL
    command DISMOUNT is entered.

2.20    /USER_NAME

       /USER_NAME[=user-name]

    Specifies a user name of up to 12 alphanumeric characters to be
    recorded on the volume. The default name is the current process
    user name.

2.21    /VOLUME_CHARACTERISTICS

       /VOLUME_CHARACTERISTICS=([[NO]HARDLINKS,] [[NO]ACCESS_
       DATES[=delta-time]])

    Enables or disables hardlinks and automatic updates of access
    dates on ODS-5 volumes.

    To limit the performance impact if a file is accessed frequently,
    you can suppress update of the access time if the change is
    small. A delta time is used to determine when a new access time
    is significant. The default value for delta-time is 1 second,
    chosen to comply with the "seconds since EPOCH" time interface
    required by POSIX st_atime. A site can choose a larger delta time
    to reduce overhead if 1-second granularity is not required.

    To disable access date support on a volume, use the SET
    VOLUME/VOLUME_CHARACTERISTICS=NOACCESS_DATES command. This
    command affects only the node on which the command is issued.
    Other nodes are not affected by the change until the next time
    the volume is mounted.

2.22    /WINDOWS

       /WINDOWS[=n]

    Specifies the number of mapping pointers to be allocated for file
    windows.

    The value of n can be from 7 to 80; the default value is 7.

2.23    /WRITETHROUGH

       /WRITETHROUGH
       /NOWRITETHROUGH

    This qualifier only affects applications such as PATHWORKS that
    can request deferred writes to file headers. You use it to
    control whether these applications can use the deferred write
    feature.

    Use /NOWRITETHROUGH to allow these applications to use the
    deferred write feature. When one of these applications explicitly
    requests a deferred write when updating a file header, control
    returns to the application when the I/O request has been queued;
    the application does not have to wait until the data is on disk.

    Note that although the SHOW DEVICES/FULL command shows the volume
    status as write-back caching enabled, the extended file cache
    (XFC) will still be in write-through mode.

    Use /WRITETHROUGH to disable the deferred write feature, so that
    no applications can use it. The SHOW DEVICES/FULL command shows
    the volume status as write-through caching enabled.

    The deferred write feature is not available on Files-11 ODS-1
    volumes.

3  –  Examples

    1.$ SET VOLUME/DATA_CHECK=(READ,WRITE) DKA5

      The SET VOLUME command in this example requests that data
      checks be performed following all read and write operations
      to DKA5.

    2.$ SET VOLUME/FILE_PROTECTION=(S:RWED,O:RWED,G:RE,W:RE) DKA5

      The SET VOLUME command in this example sets the default
      protection to be applied to all files created on volume DKA5.
      System (S)  and owner (O) are granted all types of access;
      group (G)  and world (W) are permitted only to read and execute
      files on DKA5.

    3.$ SET VOLUME/LABEL=LICENSES DKA5

      The SET VOLUME command in this example encodes the label
      LICENSES on the volume DKA5. Note that if characters in labels
      are entered in lowercase, they are changed to uppercase by the
      /LABEL qualifier.

    4.$ SET VOLUME/ACCESSED=25/USER_NAME=MANAGER/LOG DKA0:

      The SET VOLUME command in this example specifies that 25
      directories are to be maintained in system space for ready
      access for the volume DKA0. The command also assigns the
      user name MANAGER to the volume and displays the volume
      specification after the volume is modified.

    5.$ SET VOLUME/REBUILD/LOG NODE$DKA2:
      %SET-I-MODIFIED, _NODE$DKA2: modified

      The SET VOLUME command in this example causes a rebuild
      operation to begin on the volume that is mounted on NODE$DKA2.
      The /LOG qualifier directs the SET VOLUME command to display a
      notification message.

    6.$ DISMOUNT/CLUSTER/NOUNLOAD $252$DUA716:
      $ MOUNT $252$DUA716: TST716
      $ SET VOLUME/LIMIT $252$DUA716:
      $ DISMOUNT/NOUNLOAD $252$DUA716:
      $ MOUNT/CLUSTER $252$DUA716: TST716

      This example shows how to increase the expansion limit of a
      volume mounted in a cluster.

    7.$ SET VOLUME SYS$DISK/VOLUME_CHARACTERISTICS=NOHARDLINKS

      This command disables hard links on SYS$DISK.

    8.$ SET VOLUME $DKA100/CACHE=CLEAR_DATA

      This command clears the contents of the volume $DKA100 present
      in the XFC cache (if any). The caching mode of the volume
      $DKA100 is not altered.

    9.$ SET VOLUME $DKA100/CACHE=DATA

      This command enables XFC caching for the volume $DKA100. The
      contents of the volume $DKA100 already present in the XFC cache
      is not affected in anyway.

    10$ SET VOLUME $DKA100/CACHE=(DATA,CLEAR_DATA)

      This command enables XFC caching for the volume $DKA100 and
      clears the contents of the volume $DKA100 present in the XFC
      cache (if any).
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