Provided by: dmsetup_1.02.05-1ubuntu1_i386 bug


       dmsetup - low level logical volume management


       dmsetup create device_name [-u uuid] [--notable] [table_file]
       dmsetup remove device_name
       dmsetup remove_all
       dmsetup suspend [--nolockfs] device_name
       dmsetup resume device_name
       dmsetup load device_name [table_file]
       dmsetup clear device_name
       dmsetup reload device_name [table_file]
       dmsetup rename device_name new_name
       dmsetup ls [--target target_type] [--exec command] [--tree [-o
       dmsetup info [device_name]
       dmsetup info -c|-C|--columns [--noheadings] [-o name] [device_name]
       dmsetup deps [device_name]
       dmsetup status [--target target_type] [device_name]
       dmsetup table [--target target_type] [device_name]
       dmsetup wait device_name [event_nr]
       dmsetup mknodes [device_name]
       dmsetup targets
       dmsetup version

       devmap_name major minor
       devmap_name major:minor


       dmsetup manages logical devices  that  use  the  device-mapper  driver.
       Devices are created by loading a table that specifies a target for each
       sector (512 bytes) in the logical device.

       The first argument to dmsetup is a command.  The second argument is the
       logical device name or uuid.

       Invoking the command as devmap_name is equivalent to
       dmsetup info -c --noheadings -j major -m minor.


              Display output in columns rather than as Field: Value lines.

       -j|--major major
              Specify the major number.

       -m|--minor minor
              Specify the minor number.

              Suppress the headings line when using columnar output.

              Tell  the  kernel not to supply the open reference count for the

              When creating a device, don’t load any table.

              Specify which fields to display.  Only -o name is supported.

              Set the table being loaded read-only.

              Specify the uuid.

              Produce additional output.

              Display the library and kernel driver version.


       create device_name [-u uuid] [--notable] [table_file]
              Creates  a  device  with  the  given  name.   If  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  a  device  will  appear  as
              /dev/device-mapper/<device-name>.   See below for information on
              the table format.

       deps   [device_name]
              Outputs a list of (major, minor) pairs for devices referenced by
              the live table for the specified device.

       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

       ls     [--target target_type] [--exec command] [--tree [-o options]]
              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.  --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; active, open, rw, uuid.  Others specify how the
              tree  is  displayed:  ascii,  utf,  vt100;  compact,   inverted,

              device_name [table_file]
              Loads  table_file  into the inactive table slot for device_name.
              If table_file is not  supplied,  reads  a  table  from  standard

       remove device_name
              Removes  a  device.  It will no longer be visible to dmsetup and
              will be deleted when its open_count is zero.

              Attempts to remove all device definitions i.e. reset the driver.
              Use with care!

       rename device_name new_name
              Renames a device.

       resume device_name
              Un-suspends  a device.  If an inactive table has been loaded, it
              becomes live.  Postponed I/O then gets re-queued for processing.

       status [--target target_type] [device_name]
              Outputs  status  information  for  each of the device’s targets.
              With --target, only information relating to the specified target
              type is displayed.

              [--nolockfs] 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.

       table  [--target target_type] [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

              Displays the names and versions of the currently-loaded targets.

              Outputs version information.

       wait   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.


       Each line of the table specifies a single target and is of the form:
           logical_start_sector num_sectors target_type target_args

       There are currently three simple target types available  together  with
       more complex optional ones that implement snapshots and mirrors.

       linear destination_device start_sector
              The traditional linear mapping.

              num_stripes chunk_size [destination start_sector]+
              Creates a striped area.
              e.g.  striped  2  32  /dev/hda1 0 /dev/hdb1 0 will map the first
              chunk (16k) as follows:
                  LV chunk 1 -> hda1, chunk 1
                  LV chunk 2 -> hdb1, chunk 1
                  LV chunk 3 -> hda1, chunk 2
                  LV chunk 4 -> hdb1, chunk 2

              Errors any I/O that goes to this area.  Useful  for  testing  or
              for creating devices with holes in them.


       # A table to join two disks together
       0 1028160 linear /dev/hda 0
       1028160 3903762 linear /dev/hdb 0

       # A table to stripe across the two disks,
       # and add the spare space from
       # hdb to the back of the volume

       0 2056320 striped 2 32 /dev/hda 0 /dev/hdb 0
       2056320 2875602 linear /dev/hdb 1028160


       Original version: Joe Thornber (


       Device-mapper resource page: