MAN page from Fedora 4 device-mapper-1.02.07-2.0.x86_64.rpm
Section: MAINTENTANCE COMMANDS (8)
Updated: Apr 06 2006Index
dmsetup - low level logical volume management
SYNOPSISdmsetup create device_name [-u uuid] [--notable] [table_file]dmsetup removedevice_namedmsetup remove_alldmsetup suspend[--nolockfs] device_namedmsetup resumedevice_namedmsetup loaddevice_name [table_file]dmsetup cleardevice_namedmsetup reloaddevice_name [table_file]dmsetup renamedevice_name new_namedmsetup ls [--target target_type] [--exec command] [--tree [-o options]]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 waitdevice_name[event_nr]dmsetup mknodes[device_name]dmsetup targetsdmsetup version
dmsetup manages logical devices that use the device-mapper driver. Devices are created by loading a table that specifies a target foreach 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
- -m|--minor minor
Specify the major number.
Specify the minor number.
Suppress the headings line when using columnar output.
Tell the kernel not to supply the open reference count for the device.
When creating a device, don't load any table.
- is supported.
Specify which fields to display. Only -o name
Set the table being loaded read-only.
Specify the uuid.
Produce additional output.
Display the library and kernel driver version.
- createdevice_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 ofdevice_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.
Outputs a list of (major, minor) pairs for devices referenced by thelive table for the specified device.
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 leastone target of the specified type. Optionally execute a command foreach 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, notrunc.
- load|reloaddevice_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 input.
Removes a device. It will no longer be visible to dmsetup andwill be deleted when its open_count is zero.
Attempts to remove all device definitions i.e. reset the driver.Use with care!
- renamedevice_name new_name
Renames a device.
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 typeis displayed.
Suspends a device. Any I/O that has already been mapped by the devicebut has not yet completed will be flushed. Any further I/O to thatdevice 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 fedback in using the create or load commands.With --target, only information relating to the specified target typeis displayed.
Displays the names and versions of the currently-loaded targets.
Outputs version information.
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 findthe 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.
- lineardestination_device start_sector
The traditional linear mapping.
- stripednum_stripes chunk_size [destination start_sector]+
Creates a striped area.
e.g. striped 2 32 /dev/hda1 0 /dev/hdb1 0will 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 orfor 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 (thornberAATTsistina.com)
Device-mapper resource page: http://sources.redhat.com/dm/
- TABLE FORMAT
- SEE ALSO
This document was created byman2html,using the manual pages.