clear device_name
Destroys the table in the inactive table slot for
device_name.
create device_name [-n|--notable|--table table|table_file]
[--readahead [+]sectors|auto|none] [-u|--uuid uuid]
[--addnodeoncreate|--addnodeonresume]
Creates a device with the given name. If table or
table_file is supplied, the table is loaded and made live.
Otherwise a table is read from standard input unless
--notable is used. The optional uuid can be used in place
of device_name in subsequent dmsetup commands. If
successful the device will appear in table and for live
device the node /dev/mapper/device_name is created. See
below for more information on the table format.
create --concise [concise_device_specification]
Creates one or more devices from a concise device
specification. Each device is specified by a comma-
separated list: name, uuid, minor number, flags, comma-
separated table lines. Flags defaults to read-write (rw)
or may be read-only (ro). Uuid, minor number and flags
are optional so those fields may be empty. A semi-colon
separates specifications of different devices. Use a
backslash to escape the following character, for example a
comma or semi-colon in a name or table. See also CONCISE
FORMAT below.
deps [-o options] [device_name...]
Outputs a list of devices referenced by the live table for
the specified device. Device names on output can be
customised by following options: devno (major and minor
pair, used by default), blkdevname (block device name),
devname (map name for device-mapper devices, equal to
blkdevname otherwise).
help [-c|-C|--columns]
Outputs a summary of the commands available, optionally
including the list of report fields.
info [device_name...]
Outputs some brief information about the device in the
form:
State: SUSPENDED|ACTIVE, READ-ONLY
Tables present: LIVE and/or INACTIVE
Open reference count
Last event sequence number (used by wait)
Major and minor device number
Number of targets in the live table
UUID
info -c|-C|--columns [--count count] [--interval seconds]
[--noheadings] [-o fields] [-O|--sort sort_fields]
[--nameprefixes] [--separator separator] [device_name]
Output you can customise. Fields are comma-separated and
chosen from the following list: name, major, minor, attr,
open, segments, events, uuid. Attributes are: (L)ive,
(I)nactive, (s)uspended, (r)ead-only, read-(w)rite.
Precede the list with '+' to append to the default
selection of columns instead of replacing it. Precede any
sort field with '-' for a reverse sort on that column.
ls [--target target_type] [-o options] [--exec command] [--tree]
List device names. Optionally only list devices that have
at least one target of the specified type. Optionally
execute a command for each device. The device name is
appended to the supplied command. Device names on output
can be customised by following options: devno (major and
minor pair, used by default), blkdevname (block device
name), devname (map name for device-mapper devices, equal
to blkdevname otherwise). --tree displays dependencies
between devices as a tree. It accepts a comma-separate
list of options. Some specify the information displayed
against each node: device/nodevice; blkdevname; active,
open, rw, uuid. Others specify how the tree is displayed:
ascii, utf, vt100; compact, inverted, notrunc.
load|reload device_name [--table table|table_file]
Loads table or table_file into the inactive table slot for
device_name. If neither is supplied, reads a table from
standard input.
mangle [device_name...]
Ensure existing device-mapper device_name and UUID is in
the correct mangled form containing only whitelisted
characters (supported by udev) and do a rename if
necessary. Any character not on the whitelist will be
mangled based on the --manglename setting. Automatic
rename works only for device names and not for device
UUIDs because the kernel does not allow changing the UUID
of active devices. Any incorrect UUIDs are reported only
and they must be manually corrected by deactivating the
device first and then reactivating it with proper mangling
mode used (see also --manglename).
message device_name sector message
Send message to target. If sector not needed use 0.
mknodes [device_name...]
Ensure that the node in /dev/mapper for device_name is
correct. If no device_name is supplied, ensure that all
nodes in /dev/mapper correspond to mapped devices
currently loaded by the device-mapper kernel driver,
adding, changing or removing nodes as necessary.
remove [-f|--force] [--retry] [--deferred] device_name...
Removes a device. It will no longer be visible to
dmsetup. Open devices cannot be removed, but adding
--force will replace the table with one that fails all
I/O. --deferred will enable deferred removal of open
devices - the device will be removed when the last user
closes it. The deferred removal feature is supported since
version 4.27.0 of the device-mapper driver available in
upstream kernel version 3.13. (Use dmsetup version to
check this.) If an attempt to remove a device fails,
perhaps because a process run from a quick udev rule
temporarily opened the device, the --retry option will
cause the operation to be retried for a few seconds before
failing. Do NOT combine --force and --udevcookie, as udev
may start to process udev rules in the middle of error
target replacement and result in nondeterministic result.
remove_all [-f|--force] [--deferred]
Attempts to remove all device definitions i.e. reset the
driver. This also runs mknodes afterwards. Use with
care! Open devices cannot be removed, but adding --force
will replace the table with one that fails all I/O.
--deferred will enable deferred removal of open devices -
the device will be removed when the last user closes it.
The deferred removal feature is supported since version
4.27.0 of the device-mapper driver available in upstream
kernel version 3.13.
rename device_name new_name
Renames a device.
rename device_name --setuuid uuid
Sets the uuid of a device that was created without a uuid.
After a uuid has been set it cannot be changed.
resume device_name... [--addnodeoncreate|--addnodeonresume]
[--noflush] [--nolockfs] [--readahead
[+]sectors|auto|none]
Un-suspends a device. If an inactive table has been
loaded, it becomes live. Postponed I/O then gets re-
queued for processing.
setgeometry device_name cyl head sect start
Sets the device geometry to C/H/S.
splitname device_name [subsystem]
Splits given device name into subsystem constituents. The
default subsystem is LVM. LVM currently generates device
names by concatenating the names of the Volume Group,
Logical Volume and any internal Layer with a hyphen as
separator. Any hyphens within the names are doubled to
escape them. The precise encoding might change without
notice in any future release, so we recommend you always
decode using the current version of this command.
stats command [options]
Manages IO statistics regions for devices. See dmstats(8)
for more details.
status [--target target_type] [--noflush] [device_name...]
Outputs status information for each of the device's
targets. With --target, only information relating to the
specified target type any is displayed. With --noflush,
the thin target (from version 1.3.0) doesn't commit any
outstanding changes to disk before reporting its
statistics.
suspend [--nolockfs] [--noflush] device_name...
Suspends a device. Any I/O that has already been mapped
by the device but has not yet completed will be flushed.
Any further I/O to that device will be postponed for as
long as the device is suspended. If there's a filesystem
on the device which supports the operation, an attempt
will be made to sync it first unless --nolockfs is
specified. Some targets such as recent (October 2006)
versions of multipath may support the --noflush option.
This lets outstanding I/O that has not yet reached the
device to remain unflushed.
table [--concise] [--target target_type] [--showkeys]
[device_name...]
Outputs the current table for the device in a format that
can be fed back in using the create or load commands.
With --target, only information relating to the specified
target type is displayed. Real encryption keys are
suppressed in the table output for crypt and integrity
targets unless the --showkeys parameter is supplied.
Kernel key references prefixed with : are not affected by
the parameter and get displayed always (crypt target
only). With --concise, the output is presented concisely
on a single line. Commas then separate the name, uuid,
minor device number, flags ('ro' or 'rw') and the table
(if present). Semi-colons separate devices. Backslashes
escape any commas, semi-colons or backslashes. See
CONCISE FORMAT below.
targets
Displays the names and versions of the currently-loaded
targets.
udevcomplete cookie
Wake any processes that are waiting for udev to complete
processing the specified cookie.
udevcomplete_all [age_in_minutes]
Remove all cookies older than the specified number of
minutes. Any process waiting on a cookie will be resumed
immediately.
udevcookie
List all existing cookies. Cookies are system-wide
semaphores with keys prefixed by two predefined bytes
(0x0D4D).
udevcreatecookie
Creates a new cookie to synchronize actions with udev
processing. The output is a cookie value. Normally we
don't need to create cookies since dmsetup creates and
destroys them for each action automatically. However, we
can generate one explicitly to group several actions
together and use only one cookie instead. We can define a
cookie to use for each relevant command by using
--udevcookie option. Alternatively, we can export this
value into the environment of the dmsetup process as
DM_UDEV_COOKIE variable and it will be used automatically
with all subsequent commands until it is unset. Invoking
this command will create system-wide semaphore that needs
to be cleaned up explicitly by calling udevreleasecookie
command.
udevflags cookie
Parses given cookie value and extracts any udev control
flags encoded. The output is in environment key format
that is suitable for use in udev rules. If the flag has
its symbolic name assigned then the output is
DM_UDEV_FLAG_<flag_name> = '1',
DM_UDEV_FLAG<flag_position> = '1' otherwise. Subsystem
udev flags don't have symbolic names assigned and these
ones are always reported as
DM_SUBSYSTEM_UDEV_FLAG<flag_position> = '1'. There are 16
udev flags altogether.
udevreleasecookie [cookie]
Waits for all pending udev processing bound to given
cookie value and clean up the cookie with underlying
semaphore. If the cookie is not given directly, the
command will try to use a value defined by DM_UDEV_COOKIE
environment variable.
version
Outputs version information.
wait [--noflush] device_name [event_nr]
Sleeps until the event counter for device_name exceeds
event_nr. Use -v to see the event number returned. To
wait until the next event is triggered, use info to find
the last event number. With --noflush, the thin target
(from version 1.3.0) doesn't commit any outstanding
changes to disk before reporting its statistics.
wipe_table device_name... [-f|--force] [--noflush] [--nolockfs]
Wait for any I/O in-flight through the device to complete,
then replace the table with a new table that fails any new
I/O sent to the device. If successful, this should
release any devices held open by the device's table(s).
