DMSETUP(8) MAINTENTANCE COMMANDS DMSETUP(8)
dmsetup - low level logical volume management
dmsetup create device_name [-u uuid] [--notable] [table_file]
dmsetup remove device_name
dmsetup suspend 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 info [device_name]
dmsetup deps [device_name]
dmsetup status [device_name]
dmsetup table [device_name]
dmsetup wait device_name [event_nr]
dmsetup mknodes [device_name]
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.
Specify the major number to use on creation.
Specify the minor number to use on creation.
Set the table being loaded read-only.
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 sup-
plied, 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
Outputs a list of (major, minor) pairs for devices referenced by
the live 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
List device names.
Loads table_file into the inactive table slot for device_name.
If table_file is not supplied, reads a table from standard
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.
Un-suspends a device. If an inactive table has been loaded, it
becomes live. Postponed I/O then gets re-queued for processing.
Outputs status information for each of the device's targets.
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
Outputs the current table for the device in a format that can be
fed back in using the create or load commands.
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 (thornberATsistina.com)
Device-mapper resource page: http://sources.redhat.com/dm/
Linux Sep 17 2003 DMSETUP(8)