admldisk(1M) DG/UX 5.4.2 admldisk(1M)
NAME
admldisk - manage logical disks
SYNOPSIS
admldisk -o list [ -qvip ] [ name ] ...
admldisk -o create { -P
physicaldiskname:startingblock:blockcount[:piecenumber]
} ... [ -s stripesize ] name
admldisk -o remove [ -q ] name ...
admldisk -o remove [ -q ] [ -P
physicaldiskname:startingblock:blockcount:piecenumber ]
... name
admldisk -o expand [ -q ] -P
physicaldiskname:startingblock:blockcount name
admldisk -o shrink [ -q ] -n blockstoshrink name
admldisk -o copy [ -q ] -s logicaldiskname[:piecenumber] -d
logicaldiskname[:piecenumber]
admldisk -o copy -s logicaldiskname[:piecenumber] -d -
admldisk -o copy [ -q ] -s - -d logicaldiskname[:piecenumber]
DESCRIPTION
The admldisk command manages logical disks. A logical disk is an
abstraction which presents one or pieces from one or more physical
disks as a single unit. Logical disks are usually used to hold DG/UX
file systems, or as swap devices, but are also used for raw storage
for database management systems and the like. Currently, each
logical disk must be made up of one or more pieces of one or more
physical disks (see admpdisk(1M)). This may change in a future
release of DG/UX.
If any piece of a logical disk is unavailable, due to a physical disk
being unavailable or unregistered, then the logical disk will not be
available for I/O or mounting. Such a disk is said to be 'unusable'.
If two or more logical disks are defined with the same name, only one
will be considered to be usable, even if no pieces are missing from
the others (this is an unusual situation).
A logical disk can be striped. A striped logical disk must be made up
of two or more pieces, all of the same size, and all resident on
separate physical disks. Each striped logical disk has a stripe
size, which must be 1, 2, 4, 8, or 16 blocks. The first stripe size
blocks are stored on the first disk piece of the logical disk; the
next stripe size of blocks are stored on the second disk piece, etc.,
rotating among all the disk pieces that compose the logical disk.
The size of the disk pieces must be an integral multiple of the
stripe size. A striped logical disk cannot be expanded or shrunk.
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Logical disks may be combined to form mirrors. A mirror is a
collection of one to three logical disks that store data redundantly
(see admmdisk(1M)). When logical disks are incorporated into
mirrors, the individual logical disks are referred to as 'images'. A
logical disk that is an image of a mirror cannot be removed,
expanded, shrunk, or be the source or destination of a copy
operation.
Normally, for each logical disk, there are entries with that disk's
name in /dev/dsk and /dev/rdsk. However, when logical disks are
combined to form a mirror, only the mirror has such an entry.
Operations
list Displays information about the logical disks named on the
command line, or, if no logical disks are named on the
command line (or "all" is specified), all logical disks
that are part of any registered physical disk are listed.
By default, the output consists of one line per logical
disk, containing:
the name of the logical disk,
the size of the logical disk in blocks,
the stripe size of the logical disk (if it is
striped),
an indication of whether the logical disk is usable,
and
the name of the mirror of which this logical disk is
an image (if any), or "<none>".
If the -p option is specified on the command line, then in
addition to the one line describing the whole logical disk,
there is one output line per disk piece, which contains:
the number of the piece within the logical disk,
the total number of pieces in the logical disk,
the address on the physical disk of the piece,
the size of the piece in blocks, and
the name of the physical disk upon which the piece
resides.
create Creates a new logical disk out of the disk piece(s)
specified with the -P option. At least one piece must be
specified. The logical disk name must be made up of
printing characters (as defined by isprint(1)), and may not
include any of the characters ( ) / + : space or tab.
remove Removes one or more whole logical disk(s), or, with the -P
option, removes specific piece(s) of a logical disk. The
-P option must be used if some piece(s) of a logical disk
are already missing, and you wish to reclaim the disk space
occupied by the remaining piece(s). This operation should
not be used to shrink a logical disk.
expand Expands the named logical disk by adding the disk piece
specified with the -P option to the end of the logical
disk. This has no effect on the contents of the logical
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disk. The new blocks are not initialized to any particular
value. Striped logical disks cannot be expanded. If the
logical disk contains a file system, admfilesystem, not
admldisk, should be used to expand the file system and the
logical disk together.
shrink Shrinks the named logical disk by the number of blocks
specified with the -n option. Any data that was in the
blocks that were removed is essentially lost, but may not
be erased from the physical disk. Striped logical disks
cannot be shrunken. If the logical disk contains a file
system, admfilesystem, not admldisk, should be used to
shrink the file system and the logical disk together.
copy Copies whole logical disks, or pieces of logical disks.
The source and destination need not be the same size. Both
source and destination must be either usable logical disks,
or pieces of logical disks that are usable; or the standard
input or standard output of the admldisk process. Admldisk
cannot copy to or from a piece of a striped logical disk.
Options
The following options may be used with the list, remove, expand,
shrink, and copy operations.
-q Quiet. With the list operation, no headers are output, and
the fields are separated by colons rather than white space.
With the other operations, the user is not asked to confirm
before the operation is performed.
The following options may be used with the list operation.
-v Verbose. This is the default.
-i Incomplete. Include in the listing logical disks that are
incomplete (i.e. for which one or more pieces are
missing), or otherwise unusable. By default, such disks
are not listed, because without all their pieces they do
not constitute usable logical disks.
-p Pieces. As described above, in addition to one line of
output per logical disk, one line of output per logical
disk piece is produced.
If both -i and -p are specified, missing pieces are listed
with the string '<MISSING>' instead of the physical
address, length, and physical disk name.
The following option must be used with the create and expand
operations, and may be used with the remove operation.
-P physicaldiskname:startingblock:blockcount[:piecenumber]
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-P physicaldiskname:*:blockcount[:piecenumber]
Piece of a physical disk. :piecenumber is optional with
the create operation. If no piecenumbers are specified to
the create operation, the pieces are used in the order that
they are given on the command line (each piece must be
specified as a separate -P option). :piecenumber is
mandatory when the -P option is used with the remove
operation. With the expand operation, piecenumber is not
allowed.
The second form (with * in place of startingblock) may be
used with the create and expand operations. With this
form, admldisk chooses the location on the physical disk.
Note that the '*' character may be interpreted by the shell
unless it (or the whole -P option) is quoted.
The following option may be used with the create operation.
-s stripesize
Stripe the logical disk onto its pieces. If a stripesize
of 0 is specified, the largest legal stripe size less than
or equal to 16 is used. Stripesize expresses the stripe
size in blocks.
It makes little sense to use this software striping
facility on a HADA (Highly Available Disk Array) 'physical
disk', as these devices do striping at the hardware level.
Moreover, doing so could have an adverse affect on
performance. However, there is nothing to prevent you from
doing so.
There can be adverse performance consequences to using a
stripe size that is too small. In particular, if the size
of data elements [see mkfs (1M)] in the DG/UX file system
that occupies the logical disk is greater than stripe size,
performance can be degraded.
The following option must be used with the shrink operation.
-n blockstoshrink
Number. Number of blocks to trim from the end of the
logical disk.
The following options are with the copy operation.
-s logicaldiskname[:piecenumber]
Source. This specifies the source of the copy operation.
If :piecenumber is not included, the whole logical disk is
used. If '-' is specified, admldisk's standard input is
read.
-d logicaldiskname[:piecenumber]
Destination. This specifies the destination of the copy
operation. If :piecenumber is not included, the whole
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logical disk is used. If '-' is specified, output is
written to admldisk's standard output.
DIAGNOSTICS
Exit Codes
0 The operation was successful.
1 The operation was unsuccessful.
2 The operation failed due to access restrictions.
3 There was an error in the command line.
SEE ALSO
admpdisk(1M), admmdisk(1M), mkfs(1M).
NOTES
The design of the logical disk and mirror subsystem may change in a
future release of the DG/UX System.
To copy a piece of an unusable logical disk (e.g. one for which a
piece is missing), you must remove the logical disk definition, and
create a temporary logical disk definition containing just the
piece(s) to be copied.
The names all and allusable are reserved, you may not create a
logical disk with either of these names.
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