- Device mapper
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In the Linux kernel, the device-mapper serves as a generic framework to map one block device onto another. It forms the foundation of LVM2 and EVMS, software RAIDs, dm-crypt disk encryption, and offers additional features such as file-system snapshots.
Device-mapper works by processing data passed in from a virtual block device, that it itself provides, and then passing the resultant data on to another block device.
Contents
Applications
Applications (like LVM2 and EVMS) that need to create new mapped devices talk to the device-mapper via the libdevmapper.so shared library, which in turn issues ioctls to the /dev/mapper/control device node. Developers can also access device-mapper from shell scripts via the dmsetup tool.
Device mapper applications
- LVM2
- EVMS
- kpartx
- dm-crypt
- dmraid (providing access to RAID configurations via device-mapper)
- cryptoloop (deprecated)
- Multipath (using device-mapper-multipath[1])
- The Linux version of TrueCrypt
- dmcache A generic block-level disk cache
External links
- Device mapper home at Red Hat
- "Right To Your Own Devices". Linux Gazette. May 2005. http://linuxgazette.net/114/kapil.html. — an article that illustrates the use of various device-mapper targets
- userspace tool to set up software RAID using various RAID metadata formats
- Multipath support in the device mapper--LWN.net
References
Categories:- Linux kernel features
- Linux stubs
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