If you do not specify a logical name for a magnetic tape drive, the
MOUNT command assigns only one logical name, TAPE$volume-label, to the
first magnetic tape device in the list. No default logical volume-set
name is assigned in this case.
The MOUNT command places the name in the process logical name table,
unless you specify /GROUP or /SYSTEM. In the latter cases, it places
the logical names in the group or system logical name table.
If you specify the /CLUSTER qualifier, the logical name is established
on each node in the cluster.
Do not use the logical name assigned to a volume as a distributed file
system (DFS) access point. If you attempt to add a DFS access point
using the same name as the logical name, DFS fails as in the following
example:
If the logical name of a volume is in a process-private table, then the
name is not deleted when the volume is dismounted.
The Mount command (MOUNT) is used to make a disk or magnetic tape
available for processing. MOUNT allows you to ensure that the device
has not been allocated to another user, that a volume is physically
loaded on the device specified, and that the label on the volume
matches the label specified.
For magnetic tape volumes, MOUNT also checks the volume accessibility
field of the VOL1 label.
Normally, MOUNT allocates the device to the user who enters the
command. However, mounting volumes with the /SHARE, /GROUP, or /SYSTEM
qualifier deallocates the device, because the purpose of these
qualifiers is to make the volume shareable.
Note
To mount a volume on a device, you must have read (R) or control (C)
access to that device.
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Any subprocess in the process tree can mount or dismount a volume for
the job. When a subprocess mounts a volume (for the job) as private,
the master process of the job becomes the owner of this device. This
provision is necessary because the subprocess may be deleted and the
volume should remain privately mounted for this job. However, when a
subprocess explicitly allocates a device and then mounts a private
volume on this device, the subprocess retains device ownership. In this
situation, only subprocesses with SHARE privilege have access to the
device.
Upon successful completion of the operation, MOUNT notifies you with a
message sent to SYS$OUTPUT. If the operation fails for any reason,
MOUNT notifies you with an error message.
Certain file utilities such as MOUNT allocate virtual memory to hold
copies of the index file and storage bitmaps. Beginning with larger
bitmaps in OpenVMS Version 7.2, the virtual memory requirements of
these utilities increase correspondingly. To use MOUNT on volumes with
large bitmaps, you might need to increase your page file quota. On
OpenVMS VAX systems, you might also need to increase the system
parameter VIRTUALPAGECNT.
The virtual memory size is shown as VAX pages (or Alpha 512-byte
pagelets) per block of bitmap. Note that the size of the index file
bitmap in blocks is the maximum number of files divided by 4096. The
virtual memory requirements for MOUNT is equal to the sum of the sizes
of all index file bitmaps and storage bitmaps on the volume set. This
requirement applies to MOUNT only if you rebuild a volume.
If you have a disk volume that you do not want the file system to
cache, such as a database volume, use the /NOCACHE qualifier. This
disables caching for the volume:
- It stops the following metadata caches from caching any metadata
for the volume on the local node:
The Extent Cache
The File Identifier Cache
The Quota Cache
- It stops the local Extended File Cache or Virtual I/O Cache from
caching any files in the volume.
MOUNT Usage Summary
The Mount command (MOUNT) makes a disk or magnetic tape volume
available for processing.
To invoke MOUNT, enter the DCL command MOUNT, followed by the device
name, volume label, and logical name. You must include a device name
and a volume label (unless you specify /OVERRIDE=IDENTIFICATION or use
the /FOREIGN or /NOLABEL qualifier); the logical name is optional.
MOUNT returns you to the DCL level after it either successfully
completes the operation or fails, generating an error message. If you
press Ctrl/Y or Ctrl/C, MOUNT aborts the operation and returns you to
the DCL prompt.
You can direct output from MOUNT operations with the /COMMENT and
/MESSAGE qualifiers. When the mount operation requires operator
assistance, use /COMMENT to specify additional information to be
included with the operator request. The /COMMENT text string is sent to
the operator log file and to SYS$OUTPUT. The string must contain no
more than 78 characters.
Use the /MESSAGE qualifier (this is the default) to send mount request
messages to your current SYS$OUTPUT device. If you specify /NOMESSAGE
during an operator-assisted mount, messages are not sent to SYS$OUTPUT;
the operator sees them, however, if an operator terminal is enabled to
receive messages.
Many MOUNT qualifiers require special privileges. Some qualifiers
require different privileges according to which qualifier keyword you
specify. See the individual qualifiers for details.
The following table lists MOUNT qualifiers that require special
privileges:
| Qualifier |
Keywords |
Required Privilege |
|
/ACCESSED
|
|
OPER
|
|
/CACHE=
|
[NO]EXTENT[=n]
|
OPER
|
|
|
[NO]FILE_ID[=n]
|
OPER
|
|
|
[NO]QUOTA[=n]
|
OPER
|
|
/FOREIGN
|
|
VOLPRO
1
|
|
/GROUP
|
|
GRPNAM
|
|
/MULTI_VOLUME
|
|
VOLPRO
|
|
/OVERRIDE=
|
ACCESSIBILITY
|
VOLPRO
1
|
|
|
EXPIRATION
|
VOLPRO
1
|
|
|
LOCK
|
VOLPRO
1
|
|
|
SHADOW
|
VOLPRO
1
|
|
/OWNER_UIC=
|
uic
|
VOLPRO
1
|
|
/PROCESSOR=
|
UNIQUE
|
OPER
|
|
|
SAME:device
|
OPER
|
|
|
file-spec
|
OPER and CMKRNL
|
|
/PROTECTION=
|
code
|
VOLPRO
1
|
|
/QUOTA
|
|
VOLPRO
1
|
|
/SYSTEM
|
|
SYSNAM
|
|
/WINDOWS=
|
n
|
OPER
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/ACCESSED=n
Specifies, for ODS-1 disk volumes, the approximate number of
directories that will be in use concurrently on the volume. (The
/ACCESSED qualifier is meaningless for ODS-2 volumes.)
Specify a value from 0 to 255 to override the default that was
specified when the volume was initialized.
You need the user privilege OPER to use /ACCESSED.
Example
The following command requests the volume labeled WORK to be mounted on
DKA1, specifying 150 as the number of active directories on the volume:
$ MOUNT/ACCESSED=150 DKA1 WORK
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/ASSIST (default)
/NOASSIST
Directs the mount operation to allow operator or user intervention if
the mount request fails.
When you specify the /ASSIST qualifier, MOUNT notifies the user and
certain classes of operator if a failure occurs during the mount
operation. If a failure occurs, the operator or user can either abort
the operation or correct the error condition to allow the operation to
continue.
The operator-assist messages are sent to all operator terminals that
are enabled to receive messages; magnetic tape mount requests go to
TAPE and DEVICE operators, and disk mount requests go to DISK and
DEVICE operators. Thus, if you need operator assistance while mounting
a disk device, a message is sent to DISK operators. See the description
of the REPLY command for more information about enabling and disabling
operator terminals.
Any operator reply to a mount request is written to SYS$OUTPUT to be
displayed on the user's terminal or written in a batch job log.
If no operator terminal is enabled to receive and respond to a mount
assist request, a message is displayed informing the user of the
situation. If a volume is placed in the requested drive, no additional
operator response is necessary. If the mount request originates from a
batch job and no operator terminal is enabled to receive messages, the
mount is aborted. Refer to the OpenVMS System Messages: Companion Guide for Help Message Users for a description of the
error messages and their suggested user actions.
The default is /ASSIST and can be overridden by /NOASSIST.
Example
The following command mounts an HSG80 Fibre Channel disk volume labeled
DOC and assigns the logical name WORK. The /NOASSIST qualifier signals
MOUNT that no operator intervention is necessary.
$ MOUNT/NOASSIST $1$DGA0: DOC WORK
%MOUNT-I-MOUNTED, DOC mounted on _$1$DGA0: (NODE)
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/AUTOMATIC (default)
/NOAUTOMATIC
Determines whether MOUNT enables or disables automatic volume switching
and labeling for magnetic tape or ISO 9660 CD-ROM.
Magnetic Tape
If you have multiple magnetic tape drives allocated to a volume set,
the magnetic tape ancillary control process (MTACP) performs the volume
switch by sequentially selecting the next available drive allocated to
the volume set. The MTACP expects the next reel of the volume set to be
loaded on that drive.
If the MTACP is writing to the volume set, it creates a label and
initializes the magnetic tape with that label and the protections
established for the first magnetic tape of the volume set. If it is
reading from the volume set, the MTACP generates the label and attempts
to mount the next magnetic tape with that label. If the drive has the
wrong magnetic tape (or no magnetic tape) loaded, the MTACP sends a
message to the operator's console to prompt for the correct magnetic
tape.
The label generated by the MTACP fills the 6-character volume
identifier field. The first four characters of the field contain the
first four characters of the label specified in the MOUNT command,
padded with underscores when the label is not at least four characters.
The fifth and sixth characters contain the relative volume number for
this reel in the volume set.
If you specify /NOAUTOMATIC, the MTACP requires operator intervention
to switch to the next drive during end-of-tape processing, and requires
that the operator specify a label for each new reel added to a volume
set.
ISO 9660 CD-ROM
Under ISO 9660, not all volume-set members must be mounted to perform
I/O operations against that volume set. By default, if I/O operations
attempt to access an unmounted volume-set member, an operator message
is sent to all DISK CLASS operators for system-mounted volume sets, or
the owning process for privately mounted volume sets. The message
specifies the volume-set member to mount to complete the I/O operation
requested. If /NOAUTOMATIC is specified, then an I/O operation to a
nonmounted volume set member completes with an error message
SS$_DEVNOTMOUNT.
Example
The following command instructs MOUNT not to generate its own label for
the second volume, but to use the ones supplied with the MOUNT command
instead. If the second volume is not already labeled, then the operator
must use REPLY/INIT and supply the second label.
$ MOUNT/NOAUTOMATIC MTA0: ABCD,EFGH
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/BIND=volume-set-name
Creates a volume set of one or more disk volumes or adds one or more
volumes to an existing volume set.
The parameter, volume-set-name, specifies a 1- to
12-alphanumeric-character name identifying the volume set.
An ISO 9660 volume-set name can be from 1 to 128 characters in length.
OpenVMS requires volume-set names to be unique in the first 12
characters. In addition, if the first 12 characters of volume-set name
are the same as the first 12 characters of any volume label, a lock
manager deadlock will occur. To avoid this problem, you must override
either the volume label (by using the /OVERRIDE qualifier) or the
volume-set name (by using the /BIND qualifier).
You must specify the /BIND qualifier when you first create the volume
set or each time you add a volume to the set. To dismount an individual
volume of the volume set, you must use the DISMOUNT qualifier /UNIT;
otherwise, dismounting an individual volume dismounts the entire volume
set.
When you create a volume set, the volumes specified in the volume-label
list are assigned relative volume numbers based on their positions in
the label list. The first volume specified becomes the root volume of
the set.
When you add a volume or volumes to a volume set, the first volume
label specified must be that of the root volume, or the root volume
must already be on line.
Note that if you attempt to create a volume set from two or more
volumes that already contain files and data, the file system does not
issue an error message when you issue the MOUNT/BIND command. However,
the volumes are unusable as a volume set because the directory
structures are not properly bound.
If you mount an ISO 9660 volume using the /SYSTEM or /CLUSTER
qualifier, and the volume label is not unique within the first 12
characters, you must supply an alternate 12-character volume label
using the qualifier /BIND=volume-set-name. If you choose this option,
then Mount verification is disabled for the device.
Note
Once a volume is bound into a volume set, it cannot easily be unbound.
To unbind a bound volume set (BVS):
- Do an image backup of the BVS.
- Initialize all volumes of the BVS.
- Do an image restore to a single volume with the /NOINITIALIZE
qualifier, or do a nonimage restore to a single volume.
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Examples
The following command creates a volume set named LIBRARY. This volume
set consists of the volumes labeled BOOK1, BOOK2, and BOOK3, which are
mounted physically on devices DMA0, DMA1, and DMA2, respectively.
$ MOUNT/BIND=LIBRARY DMA0:,DMA1:,DMA2: BOOK1,BOOK2,BOOK3
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The following command creates a volume set with the logical name TEST3.
The volume set TEST3 is shadowed, and each element of the volume set
(TEST3011 and TEST3012) is itself a shadowset.
$ MOUNT/BIND=TEST3 DSA3011/SHADOW=($1$DUA402:,$1$DUA403:),
DSA3012/SHADOW=($1$DUA404:,$1$DUA405:) TEST3011,TEST3012 TEST3
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/BLOCKSIZE=n
Specifies the default block size for magnetic tape volumes.
The parameter, n, specifies the default block size value for
magnetic tape volumes. Valid values are in the range 20 to 65,532 for
OpenVMS RMS operations, and 18 to 65,534 for non OpenVMS RMS
operations. By default, records are written to magnetic tape volumes in
2048-byte blocks. For foreign or unlabeled magnetic tapes, the default
is 512 bytes.
You must specify /BLOCKSIZE in two situations:
- When mounting magnetic tapes that do not have HDR2 labels. For
these magnetic tapes, you must specify the block size. For example, you
must specify /BLOCKSIZE=512 to mount an RT-11 magnetic tape.
- When mounting magnetic tapes that contain blocks whose sizes exceed
the default block size (2048 bytes). In this case, specify the size of
the largest block for the block size.
Example
In the following example, the /BLOCKSIZE qualifier specifies a block
size of 1000 bytes; the default for a magnetic tape mounted with the
/FOREIGN qualifier is 512.
$ MOUNT/FOREIGN/BLOCKSIZE=1000 MTA1:
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/CACHE=(keyword[,...])
/NOCACHE
For disks, controls whether caching limits established at system
generation time are disabled or overridden. With the TAPE_DATA option,
enables write caching for the tape controller specified (if the tape
controller supports write caching).
The following table lists the keywords for this qualifier:
| Keyword |
Description |
|
EXTENT[=n] and NOEXTENT
|
Enable or disable extent caching. To enable extent caching, you must
have the operator user privilege (OPER) and you must specify
n, the number of entries in the extent cache. Note that
NOEXTENT is equivalent to EXTENT=0; both disable extent caching.
|
|
FILE_ID[=n] and NOFILE_ID
|
Enable or disable file identification caching. To enable file
identification caching, you must have the operator user privilege
(OPER) and you must specify
n, the number of entries, as a value greater than 1. Note that
NOFILE_ID is equivalent to FILE_ID=1; both disable file identification
caching.
|
|
LIMIT=n
|
Specifies the maximum amount of free space in the extent cache in
one-thousandths of the currently available free space on the disk.
|
|
QUOTA[=n] and NOQUOTA
|
Enable or disable quota caching. To enable quota caching, you must have
the operator user privilege (OPER) and you must specify
n, the number of entries in the quota cache. Normally
n is set to the maximum number of active users expected for a
disk with quotas enabled. Both NOQUOTA and QUOTA=0 disable quota file
caching.
|
|
TAPE_DATA
|
Enables write caching for a magnetic tape device if the tape controller
supports write caching. The /CACHE qualifier is the default for
mounting tape devices. You must specify TAPE_DATA to enable write
caching. If the tape controller does not support write caching, the
keyword is ignored.
The write buffer stays enabled even after you dismount the magnetic
tape. To disable the write buffer, mount a tape with the /NOCACHE
qualifier.
If a tape supports compaction, then the default is compaction, and
caching is enabled. For tape storage devices that support compaction,
the following command is valid:
$ MOUNT TAPE_DATA/FOREIGN/MEDIA=NOCOMPACTION/NOCACHE
|
|
WRITETHROUGH
|
Disables the deferred write feature for file headers. By default, this
feature is enabled, which improves the performance of applications,
such as PATHWORKS, that use it. The deferred write feature is not
available on Files-11 ODS-1 volumes.
|
Used with the disk options, the /CACHE qualifier overrides one or more
of the present disk caching limits established at system generation
time. Used with the TAPE_DATA option, the /CACHE qualifier enables
write caching for the tape controller specified.
If you do not specify the /CACHE qualifier and it is not implied by the
use of the qualifier /MEDIA_FORMAT=COMPACTION, caching is enabled by
default.
If you specify more than one option, separate them by commas and
enclose the list in parentheses. The options [NO]EXTENT, [NO]FILE_ID,
LIMIT, and [NO]QUOTA apply only to a disk device. The option TAPE_DATA
applies only to a tape device.
The /NOCACHE qualifier is effective only if compaction is not enabled.
If compaction is enabled (with the /MEDIA_FORMAT=COMPACTION), caching
is enabled by default.
If you specify /NOCACHE for a disk device, all caching is disabled for
this volume. Note that the /NOCACHE qualifier is equivalent to
/CACHE=(NOEXTENT,NOFILE_ID,NOQUOTA,WRITETHROUGH).
If you specify /NOCACHE for a magnetic tape device, the tape
controller's write cache is disabled for this volume.
Examples
The following command mounts an HSG80 Fibre Channel disk device labeled
FILES and assigns the logical name WORK. The /CACHE qualifier enables
an extent cache of 60 entries, a file identification cache of 60
entries, and a quota cache of 20; it disables writeback caching of file
headers.
$ MOUNT/CACHE=(EXTENT=60,FILE_ID=60,QUOTA=20,WRITETHROUGH) -
_$ $1$DGA0: FILES WORK
%MOUNT-I-MOUNTED, FILES mounted on _$1$DGA0: (NODE)
|
The following command mounts the volume TAPE on device MUA0 and
instructs MOUNT to enable the tape controller's write cache for MUA0:
$ MOUNT/CACHE=TAPE_DATA MUA0: TAPE
%MOUNT-I-MOUNTED, TAPE mounted on _NODE$MUA0:
|
/CLUSTER
Specifies that after the volume is successfully mounted on the local
node, or if it is already mounted /SYSTEM on the local node, it is to
be mounted on every other node in the existing VMScluster (that is, the
volume is mounted clusterwide).
Only system or group volumes can be mounted clusterwide. If you specify
the /CLUSTER qualifier with neither the /SYSTEM nor the /GROUP
qualifier, the default is /SYSTEM. Note that you must use a cluster
device-naming convention. Use either node$device-name or
allocation-class$device-name as required by your configuration.
You need the user privileges GRPNAM and SYSNAM, respectively, to mount
group and system volumes clusterwide.
If the system is not a member of an OpenVMS Cluster, the /CLUSTER
qualifier has no effect.
Example
The following MOUNT/CLUSTER command mounts the volume SNOWWHITE on
DOPEY$DMA1, then proceeds to mount the volume clusterwide. The SHOW
DEVICE/FULL command displays information about the volume, including
the other nodes on which it is mounted.
$ MOUNT/CLUSTER DOPEY$DMA1: SNOWWHITE DWARFDISK
%MOUNT-I-MOUNTED, SNOWWHITE mounted on _DOPEY$DMA1:
$ SHOW DEVICE/FULL DWARFDISK:
Disk $2$DMA1: (DOPEY), device type RK07, is online, mounted,
file-oriented device, shareable, served to cluster via MSCP
Server, error logging is enabled.
Error count 0 Operations completed 159
Owner process "" Owner UIC [928,49]
Owner process ID 00000000 Dev Prot S:RWED,O:RWED,G:RW,W:R
Reference count 1 Default buffer size 512
Total blocks 53790 Sectors per track 22
Total cylinders 815 Tracks per cylinder 3
Allocation class 2
Volume label "SNOWWHITE" Relative volume number 0
Cluster size 3 Transaction count 1
Free blocks 51720 Maximum files allowed 6723
Extend quantity 5 Mount count 7
Mount status System Cache name "_$255$DWARF1:XQPCACHE"
Extent cache size 64 Maximum blocks in extent cache 5172
File ID cache siz 64 Blocks currently in extent cache 0
Quota cache size 25 Maximum buffers in FCP cache 349
Volume status: ODS-2, subject to mount verification,
file high-water marking, write-through caching enabled.
Volume is also mounted on DOC, HAPPY, GRUMPY, SLEEPY, SNEEZY, BASHFUL.
|
/COMMENT=string
Specifies additional information to be included with the operator
request when the mount operation requires operator assistance.
The parameter, string, specifies a text string that is output
to the operator log file and the current SYS$OUTPUT device. The string
must contain no more than 78 characters.
Examples
The following command requests the operator to mount the disk volume
TESTSYS on the device DYA1. Notice that the /COMMENT qualifier is used
to inform the operator of the location of the volume. After the
operator places the volume in DYA1, MOUNT retries the operation. After
the operation completes, the operator request is canceled.
$ MOUNT DYA1: TESTSYS/COMMENT="Volume in cabinet 6."
%MOUNT-I-OPRQST, Please mount volume TESTSYS in device _DYA1:
Volume in cabinet 6.
%MOUNT-I-MOUNTED TESTSYS mounted on _DYA1:
%MOUNT-I-OPRQSTDON, operator request canceled - mount
completed successfully
|
The following command is the same as in the previous example. However,
in this example, because the requested device is in use, the operator
aborts the mount.
$ MOUNT DYA1: TESTSYS/COMMENT="Volume in cabinet 6."
%MOUNT-I-OPRQST, Please mount volume TESTSYS in device _DYA1:
Volume in cabinet 6.
%MOUNT-I-OPREPLY, This is a '/pending' response from the operator.
31-DEC-1990 10:27:38.15, request 2 pending by operator TTB6
%MOUNT-I-OPREPLY, This is a '/abort' response from the operator.
31-DEC-1990 10:29:59.34, request 2 aborted by operator TTB6
%MOUNT-F-OPRABORT, mount aborted by operator
|
The following command requests the operator to mount the volume TESTSYS
on the device DYA0. In this example, the operator notices that the
requested device is in use and redirects the mount to device DYA1.
