Device-mapper Resource Page


The Device-mapper is a component of the 2.6 linux kernel that supports logical volume management. It is required by LVM2 and EVMS. The original LVM (included in stock 2.4 kernels) does not use it.

If you intend to use Device-mapper, as well as including it in your kernel, you should install the userspace configuration tool (dmsetup) and library (libdevmapper).

The encryption target (dm-crypt) has its own web page at

Multipath tools are available from with documentation at


The userspace code (dmsetup and libdevmapper) is now maintained alongside the LVM2 source available from To build / install it without LVM2 use 'make device-mapper' / 'make device-mapper_install'.

Kernel patches under discussion are captured by patchwork from the dm-devel mailing list and stored at*.
A quilt tree of patches being prepared for inclusion upstream is maintained at
with archived versions at

Old kernel source code patches for 2.4 and 2.6 kernels are still available from

Old source code tarballs of the userspace tool and library are still available from
These also include kernel patches for some specific 2.4 kernels.

Mailing lists

dm-devel is the mailing list for any device-mapper-related questions and discussion.
Subscribe to this from
The list archives are at
The mailing list address is

Whenever the development source code repository is updated, email is sent to the dm-cvs mailing list. This list is run using ezmlm.
To subscribe, send an email to or
You can read the list archives at

The encryption target has its own mailing list archived at
To subscribe, send a blank email to

Source code

To access the old source code repository using CVS:
cvs -d login cvs
cvs -d checkout device-mapper
The password is cvs.

There is a web interface to CVS at

Multipath Bug Reporting

As well as using the dm-devel mailing list, we are using to record multipath bugs and feature requests.
Display outstanding multipath bugzilla entries. Report multipath bug. Enter multipath feature request.


There are README, INSTALL, WHATS_NEW_DM libdevmapper.h and dmsetup man page in the LVM2 source package.

The LVM HOWTO is at


Channel #device-mapper on freenode

Related projects

The original LVM: