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Understanding Device-mapper in Linux 2.6 Kernel (Doc ID 456239.1)

Last updated on FEBRUARY 14, 2022

Applies to:

Linux OS - Version 2.6 to 2.6
Oracle Cloud Infrastructure - Version N/A and later
Linux x86
Linux x86-64
Linux Kernel - Version: 2.6 to 2.6 *** ***


Device-mapper is a very important component of Linux 2.6 kernel. It is used for many critical storage related applications, such as LVM2, Linux native multipath tool device-mapper-multipath, device-mapper software RAID, etc. A solid understanding of device-mapper helps system administrators to investigate various kinds of issues with these applications.


This bulletin is to explain the goal of device-mapper driver and it will explore the internal mechanism as well as some details of implementation. Finally there will be an example of leveraging dmsetup.


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In this Document
 1. Goal of Device-mapper
 2. Device-mapper Kernel Architecture
 2.1 Mapped Device
 2.2 Mapping Table
 2.3 Target Device
 3. How Does It Work?
 4. Device-mapper Userspace Facilities
 5. Talk to Device-mapper Driver with Dmsetup

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