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. In the Linux kernel, the device-mapper is a generic framework to map one block device into another. It is not just for LVM2. By using device-mapper, the kernel provides general services to dm-multipath, LVM2 and EVMS, device-mapper software RAIDs, dm-crypt disk encryption and offers additional features such as file system snapshots. In device-mapper architecture there are three important concepts to be familiarized 1. Mapped Device 2. Mapping Table 3. Target Device Mapped Device Mapped device is a logical device provided by device-mapper driver. It provides an interface to operate on. The logical volumes in LVM2 and pse
This blog is intended to help understand internals about linux environment. It stack together very basic and important contents, to help naive kernel users.