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volsd(8)
NAME
volsd - Perform Logical Storage Manager operations on subdisks
SYNOPSIS
/sbin/volsd [-Vf] [-g diskgroup] [-U usetype] [-o useopt] [-v volume] [-l
offset] assoc plex subdisk...
/sbin/volsd [-Vf] [-g diskgroup] [-U usetype] [-o useopt] [-v volume]
[-l[column/] offset] assoc plex subdisk[:[column/] offset]...
/sbin/volsd [-Vf] [-g diskgroup] [-U usetype] [-o useopt] [-v volume] aslog
plex subdisk
/sbin/volsd [-Vf] [-g diskgroup] [-U usetype] [-o useopt] [-v volume] [-p
plex] dis subdisk...
/sbin/volsd [-Vf] [-g diskgroup] [-U usetype] [-o useopt] [-v volume] [-p
plex] [-s size] split subdisk newsd [newsd2]
/sbin/volsd [-Vf] [-g diskgroup] [-U usetype] [-o useopt] [-v volume] [-p
plex] join sd1 sd2... newsd
/sbin/volsd [-Vf] [-g diskgroup] [-U usetype] [-o useopt] [-v volume] [-p
plex] mv oldsd newsd [newsd...]
OPTIONS
The following options are recognized:
-g diskgroup
Specifies the disk group for the operation, either by disk group ID or
by disk group name. By default, the disk group is chosen based on the
name operands.
-U usetype
Limits the operation to apply to this usage type. Attempts to affect
volumes with a different usage type will fail.
-o useopt
Passes in usage-type-specific options to the operation. A certain set
of operations are expected to be implemented by all usage types:
slow[=iodelay]
Reduces the system performance impact of copy operations. Copy
operations are usually a set of short copy operations on small
regions of the volume (normally from 16 kilobytes to 256
kilobytes). This option inserts a delay between the recovery of
each such region. A specific delay can be specified with iodelay
as a number of milliseconds, or a default is chosen (normally 250
milliseconds).
iosize=size
Performs copy operations in regions with the length specified by
size, which is a standard Logical Storage Manager length number
(see volintro(8)). Specifying a larger number typically causes the
operation to complete sooner, but with greater impact on other
processes using the volume. The default I/O size is typically 256
kilobytes.
rm Removes the subdisks after successful completion of a volsd dis
operation. Removes the source subdisk after successful completion
of volsd mv.
-V Writes a list of utilities that would be called from volsd, along with
the arguments that would be passed. The -V performs a ``mock run'' so
the utilities are not actually called.
-s size
Specifies the size for the subdisk split operation. This option takes
a standard Logical Storage Manager length number (see volintro(8)).
-l [column/]offset
Specifies the offset of a subdisk within a plex address space for the
volsd assoc operation. For striped plexes, a column number may be
optionally specified. If one number is given for striped plexes, the
number is interpreted as a column number and the subdisk is associated
at the end of the column. The offset is a standard Logical Storage
Manager length number (see volintro(8)).
-v volume
Requires that a named plex be associated with this volume, or that a
named subdisk (source subdisk for volsd split, join, and mv) be
associated with a plex that is associated with this volume.
-p plex
Requires that a named subdisk (source subdisk for volsd split, join,
and mv) be associated with this plex.
-f Forces an operation that the Logical Storage Manager considers
potentially dangerous or of questionable use. This permits a limited
set of operations that would otherwise be disallowed. Some operations
may be disallowed even with this flag.
DESCRIPTION
The volsd utility performs Logical Storage Manager operations on subdisks
and on plex-and-subdisk combinations. The first operand is a keyword that
determines the specific operation to perform. The remaining operands
specify the configuration objects to which the operation is to be applied.
Each operation can be applied to only one disk group at a time, due to
internal implementation constraints. Any plex or subdisk name operands
will be used to determine a default disk group, according to the standard
disk group selection rules described in volintro(8). A specific disk group
can be selected with -g diskgroup.
If a volsd operation is interrupted by a signal, an attempt is made to
restore the disk group configuration to a state that is roughly equivalent
to its original state. If this attempt is interrupted, such as through
another signal, the user may need to perform some cleanup. The specific
cleanup actions that are needed are written to the standard error before
volsd exits.
KEYWORDS
These are the recognized operation keywords:
assoc
Associates each named subdisk operand with the specified plex. The
first form applies to concatenated plexes (plexes with a layout of
concat). The offset within the plex for the association can be
specified with -l, which takes a standard Logical Storage Manager
length number (see volintro(8)). If no offset is specified, the default
is to associate the subdisk at the end of the plex, thus extending the
length of the plex by the length of the new subdisk.
For striped plexes, a column number for the subdisk association may be
specified. The offset is interpreted as the column offset for the
subdisk. If only one number is specified with -l for striped plexes,
the number is interpreted as a column number and the subdisk is
associated at the end of the column.
The column or column/offset at which a subdisk is to be associated can
also be specified as part of the subdisk name in the same manner as
subdisks associations are specified for plex creations in volmake (see
volmake(4)). When specifying multiple subdisks, if no column or
column/offset is specified for a subdisk, it is associated after the
previous subdisk.
A subdisk cannot be associated to overlap with an another associated
subdisk in the same plex.
If the named plex is associated with a volume, the rules for performing
the operation depend upon the usage type of the volume. A subdisk
cannot be associated to a plex if the putil0 field for the subdisk is
not empty. Creating a subdisk with the putil0 field set to a non-empty
value is a sufficient means of ensuring that no Logical Storage Manager
operation will write to the region of disk blocks allocated to the
subdisk because the subdisk cannot be associated through any means to a
plex, and because subdisks cannot be used directly to read from or
write to a disk.
aslog
Associates the named subdisk with the named plex as a log area for the
plex. At most, one log subdisk can be associated with a plex at any
given time. Currently, log subdisks can be used only with the dirty
region logging feature, as defined by the DRL volume logging type. If
the named plex is associated with a volume, the rules for performing
the operation depend upon the usage type of the volume. A subdisk
cannot be associated if the putil0 field is set on the subdisk, just as
with volsd assoc.
dis Dissociates each specified subdisk from the plex that it is associated
with. If a subdisk is associated (through its plex) with a volume, the
rules for performing the operation depend upon the usage type of the
volume.
Subdisk dissociation can be used as part of tearing down a plex, or as
part of reorganization of disk space usage. Typically, the subdisk is
no longer needed after dissociation. To support this type of use, -o
rm can be specified to remove the named subdisks after successful
dissociation.
split
Splits the subdisk subdisk into two subdisks that reside on the same
section of the same device, and that have contiguous or striped plex
associations (if the named subdisk is associated). The first of the
two resultant subdisks will have a length of size, and the second will
take up the remainder of the space used by the original subdisk. If
both newsd and newsd2 are specified, the resultant subdisks are newsd
and newsd2. If no newsd2 operand was specified, the resultant subdisks
are named subdisk and newsd.
If the named subdisk is associated with an associated plex, the rules
for performing the operation depend upon the usage type of the volume.
Log subdisks cannot be split.
join
Joins the subdisks named by the sd operands to form a new subdisk named
newsd. The sd operands must specify subdisks that represent contiguous
sections of the same device, and of the same plex (if they are
associated). For a striped plex, the sd operands must be in the same
column. At least two sd operands are required. At the end of the
operation, the sd configuration objects are removed. The newsd operand
can have the same name as one of the sd operands, or it can have a
different name.
If the sd operands are associated with an associated plex, the rules
for performing the operation depend upon the usage type of the volume.
mv Moves the contents of oldsd onto the new subdisks and replaces oldsd
with the new subdisks for any associations. If multiple new subdisks
are specified, they are associated starting where the old subdisk began
and placed consecutively with no space between them. The operation
requires that oldsd be associated with an associated plex and that all
new subdisks be dissociated. The operation can be used on a subdisk
that is used by an active volume, and will ensure that data is copied
and associations are changed without loss or corruption of data. The
rules for performing the operation depend upon the usage type of the
volume.
Moving a subdisk is the normal means of reorganizing disk space. For
example, move regions of disk used by one volume to another disk to
reduce contention on the original disk. Typically, once the operation
completes, the original subdisk is no longer needed and can be removed.
To support this use of the operation, -o rm can be specified to remove
oldsd after successful completion of the operation.
FSGEN AND GEN USAGE TYPES
The fsgen and gen usage types provide identical semantics for all
operations of the volsd utility.
In addition to the standard -o options required for all usage types, the
fsgen and gen usage types provide the following additional option:
force
Forces an operation that the Logical Storage Manager considers
potentially dangerous or of questionable use. This applies to attempts
to dissociate subdisks (making a plex sparse) and to attempts to move
subdisks onto subdisks that have a different size. This flag is the
same as -f.
Limitations and extensions for the fsgen and gen usage types consist of the
following:
assoc
If the named plex is enabled, and is associated with an enabled plex,
the named plex must be ACTIVE or EMPTY. Subdisks can be associated
with a non-enabled plex only if the utility state of the plex is EMPTY,
STALE, or OFFLINE, or if the plex is CLEAN and no other plexes
associated with the volume are CLEAN or ACTIVE.
If the subdisk is associated with a non-enabled plex, or if it is
associated with the only enabled, read-write plex in a volume, the
operation completes without copying any data onto the subdisk. If the
subdisk is associated with an enabled plex in a mirrored volume, the
operation may have to copy data from the volume onto the new subdisk
before the operation can complete.
aslog
If a log subdisk is associated with a plex that is associated with a
volume that has a logging type of UNDEF, the logging type of the volume
is converted to DRL. Logging of volume changes is not enabled until
there are at least two read-write mode plexes attached to the volume.
dis Dissociating a subdisk requires use of -f if it would cause an enabled
plex in an enabled volume to become sparse relative to the volume.
Even with -f, it is not possible to make two plexes sparse if no
complete, enabled, read-write plexes would remain associated. For
disabled volumes, a similar check is made with respect to ACTIVE and
CLEAN plexes.
split and join
The fsgen and gen usage types apply no additional restrictions and add
no extensions to the split and join operations.
mv If the total size of the destination subdisks differs from that of the
source subdisk, the -f option must be specified. The operation still
fails if the total size of the destination subdisks is larger than the
source subdisk and if the address range of any destination subdisk
would conflict with another subdisk that is associated with the plex.
The total size of the destination subdisks cannot be larger than the
source subdisk if the kernel state of the volume or plex is detached.
The operation fails if the total size of the destination subdisks is
smaller than the source subdisk and the operation would cause the total
number of complete, enabled, read-mode plexes in the volume to drop to
zero, while leaving more than one sparse, enabled, read-write plex.
RAID5 USAGE TYPE
In addition to the standard -o options required for all usage types, the
raid5 usage type provides the following additional options:
force
Forces an operation that the Logical Storage Manager considers
potentially dangerous or of questionable use. This applies to attempts
to move a subdisk in a RAID5 plex if the volume the plex is associated
with does not have a log plex. This flag is the same as -f.
The raid5 usage type supports the following keywords:
assoc
Associates the named subdisks with the named RAID5 plex. If plex is
enabled and is associated with an enabled volume, any data that maps
onto the subdisk will be regenerated from the other columns of the
RAID5 plex. This is done by marking the subdisk as stale and
writeonly, regenerating the data via VOL_R5_RECOVER ioctls, and then
turning off the stale and writeonly flags.
If the RAID5 plex is not associated or the RAID5 volume is not ENABLED,
the subdisk is associated and marked as stale. The subdisk's contents
will be recovered when the volume is started.
The assoc operation may not be used on a log plex.
dis Dissociates the named subdisks from the named RAID5 plex. If removing
the subdisk would make the volume unusable (because other subdisks in
other columns at the same altitude are unusable or missing) and the
volume is not disabled and EMPTY, the operation is not allowed. If the
volume is disabled and non-EMPTY the operation requires use of -f.
The dis operation may not be used on a log plex.
split and join
The raid5 usage type applies no additional restrictions and adds no
extensions to the split and join operations. These operations may not
be used on a log plex.
mv If the old subdisk is associated with a RAID5 plex that is associated
to a RAID5 volume, the volume must be enabled for the move operation to
complete. The mv operation is not allowed if the volume has stale
parity or has missing or stale subdisks at the same altitude as the
subdisk being replaced.
The mv operation first dissociates the old subdisk and then associates
the new subdisk in its place. It then recovers the data using
VOL_R5_RECOVER ioctls, as is done for the assoc operation. If the RAID5
volume has no valid logs, the operation requires use of -f. This is
necessary because if a crash were to occur while the data on the new
subdisks was being recovered, the parity could become stale while some
of the new subdisks are marked stale, thus rendering the volume
unusable.
The mv operation may be used on a log plex. Similar rules as those
defined for the fsgen and gen usage type plexes apply to log plexes.
The force or -f must be used to make a log plex sparse.
Note that there is no aslog operation for the raid5 usage type. Logging is
done on a plex level and therefore volsd aslog is not needed. Log plexes
can be associated with RAID5 volumes using the volplex att command.
EXIT CODES
The volsd utility exits with a nonzero status if the attempted operation
fails. A nonzero exit code is not a complete indicator of the problems
encountered, but rather denotes the first condition that prevented further
execution of the utility. See volintro(8) for a list of standard exit
codes.
FILES
/sbin/lsm.d/usetype/volsd
The utility that performs volsd operations for a particular volume
usage type.
SEE ALSO
volintro(8), volplex(8), volsd(8), volume(8)
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Index for
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Alphabetical
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