Device-mapper Resource Page

Introduction

The Device-mapper is a component of the linux kernel (since version 2.6) 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 http://www.saout.de/misc/dm-crypt/.

Multipath tools are available from ftp://sourceware.org/pub/dm/multipath-tools with documentation at http://christophe.varoqui.free.fr/.

Releases

The userspace code (dmsetup and libdevmapper) is now maintained alongside the LVM2 source available from http://sourceware.org/lvm2/. To build / install it without LVM2 use 'make device-mapper' / 'make install_device-mapper'.

Kernel patches under discussion are captured by patchwork from the dm-devel mailing list and stored at http://patchwork.kernel.org/project/dm-devel/list/?state=*.
A quilt tree of patches being prepared for inclusion upstream is maintained at http://www.kernel.org/pub/linux/kernel/people/agk/patches/2.6/editing/
with archived versions at http://www.kernel.org/pub/linux/kernel/people/agk/patches/2.6/

Old kernel source code patches for 2.4 and 2.6 kernels are still available from http://sourceware.org/dm/patches.html.

Old source code tarballs of the userspace tool and library are still available from ftp://sourceware.org/pub/dm/.
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 by sending email to dm-devel+subscribe@lists.linux.dev.
Unsubscribe by sending email to dm-devel+unsubscribe@lists.linux.dev.
The list archives are at https://lore.kernel.org/dm-devel/
The mailing list address is dm-devel@lists.linux.dev.

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 dm-cvs-subscribe@sourceware.org or dm-cvs-digest-subscribe@sourceware.org.
You can read the list archives at http://sourceware.org/ml/dm-cvs/

The encryption target has its own mailing list archived at http://news.gmane.org/gmane.linux.kernel.device-mapper.dm-crypt.
To subscribe, send a blank email to dm-crypt-subscribe@saout.de.

Source code

To access the old source code repository using CVS:
cvs -d :pserver:cvs@sourceware.org:/cvs/dm login cvs
cvs -d :pserver:cvs@sourceware.org:/cvs/dm checkout device-mapper
The password is cvs.

There is a web interface to CVS at http://sourceware.org/cgi-bin/cvsweb.cgi/device-mapper/?cvsroot=dm.

Multipath Bug Reporting

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

Documentation

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

The LVM HOWTO is at http://www.tldp.org/HOWTO/LVM-HOWTO/index.html.

IRC

Channel #device-mapper on Libera.Chat

Related projects

LVM2: http://sourceware.org/lvm2/
EVMS: http://evms.sourceforge.net/
The original LVM: http://sourceware.org/lvm/