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           dmsetup help [-c|-C|--columns]
           dmsetup create device_name [-u uuid] [--notable | --table <table> | ta-
           dmsetup remove [-f|--force] device_name
           dmsetup remove_all [-f|--force]
           dmsetup suspend [--nolockfs] [--noflush] device_name
           dmsetup resume device_name
           dmsetup load device_name [--table <table> | table_file]
           dmsetup clear device_name
           dmsetup reload device_name [--table <table> | table_file]
           dmsetup rename device_name new_name
           dmsetup message device_name sector message
           dmsetup ls [--target target_type] [--exec command] [--tree [-o
           dmsetup info [device_name]
           dmsetup info -c|-C|--columns [--noheadings] [--separator separator] [-o
           fields] [-O|--sort sort_fields] [device_name]
           dmsetup deps [device_name]
           dmsetup status [--target target_type] [device_name]
           dmsetup table [--target target_type] [--showkeys] [device_name]
           dmsetup wait device_name [event_nr]
           dmsetup mknodes [device_name]
           dmsetup udevcreatecookie
           dmsetup udevreleasecookie [cookie]
           dmsetup udevflags cookie
           dmsetup udevcomplete cookie
           dmsetup udevcomplete_all
           dmsetup udevcookies
           dmsetup targets
           dmsetup version
           dmsetup setgeometry device_name cyl head sect start
           dmsetup splitname device_name [subsystem]
           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.
                  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.
           --udevcookie cookie
                  Use cookie for udev synchronisation.
                  Do  not  allow udev to manage nodes for devices in device-mapper
                  Do not synchronise with udev when creating, renaming or removing
                  Specify which fields to display.
                  Set the table being loaded read-only.
           --readahead [+]<sectors>|auto|none
                  Specify  read ahead size in units of sectors.  The default value
                  is "auto" which allows the kernel to  choose  a  suitable  value
                  automatically.   The  +  prefix lets you specify a minimum value
                  which will not be used if it is smaller than the value chosen by
                  the kernel.  "None" is equivalent to specifying zero.
           --table <table>
                  Specify a one-line table directly on the command line.
                  Specify the uuid.
                  Answer yes to all prompts automatically.
           -v|--verbose [-v|--verbose]
                  Produce additional output.
                  Display the library and kernel driver version.


           create device_name [-u uuid] [--notable | --table <table> | table_file]
                  ing 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
           info   -c|-C|--columns  [--noheadings]  [--separator   separator]   [-o
                  fields] [-O|--sort sort_fields] [device_name]
                  Output you can customise.  Fields are comma-separated and chosen
                  from the following list: name, major, minor,  attr,  open,  seg-
                  ments,   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] [--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 <table> | table_file]
                  Loads  <table>  or  table_file  into the inactive table slot for
                  device_name.  If neither is supplied, reads a table  from  stan-
                  dard input.
                  device_name sector message
                  Send message to target. If sector not needed use 0.
                  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] device_name
                  return from them, adding --force will replace the table with one
                  that fails all I/O, which might allow the process to be  killed.
                  This also runs mknodes afterwards.
           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.
                  device_name cyl head sect start
                  Sets the device geometry to C/H/S.
                  device_name [subsystem]
                  Splits  given  device name into subsystem constituents.  Default
                  subsystem is LVM.
           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] [--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 sup-
                  ports 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  [--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  dis-
                  played.   Encryption keys are suppressed in the table output for
                  the crypt target unless the --showkeys parameter is supplied.
                  Displays the names and versions of the currently-loaded targets.
                  Creates  a  new cookie to synchronize actions with udev process-
                  ing.  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
                  value defined by DM_UDEV_COOKIE environment variable.
                  Parses  given  cookie  value and extracts any udev control flags
                  encoded.  The output is in environment key format that is  suit-
                  able  for  use  in udev rules. If the flag has its symbolic name
                  assigned  then  the   ouput   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.
                  Wake any processes that are waiting for udev  to  complete  pro-
                  cessing the specified cookie.
                  Remove  all  cookies.  Any  process  waiting on a cookie will be
                  resumed immediately.
                  List all existing cookies. Cookies  are  system-wide  semaphores
                  with keys prefixed by two predefined bytes (0x0D4D).
                  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
           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


                  The device directory name.  Defaults to "/dev" and  must  be  an
                  absolute path.
                  A  cookie  to  use for all relevant commands to synchronize with
                  udev processing.  It is an  alternative  to  using  --udevcookie


           Original version: Joe Thornber (


           Device-mapper resource page:

    Linux Apr 06 2006 DMSETUP(8)


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