device-mapper (dm): working with multipath-tools. Part 1 Filed under: SCSI, Linux — admin @ 10:33 Device-mapper (hereafter, dm) is one of the best collection of device drivers that I have ever worked with. It brings high availability, flexibility and more to the Linux 2.6 kernel. Device-mapper is a Linux 2.6 kernel infrastructure that provides a generic way to create virtual layers of a block device while supporting stripping, mirroring, snapshots, concatenation, multipathing, etc. While many modules are built on top of device-mapper, the focus of this article is on multipath-tools. Note that I will be using the terms multipath, multipath-tools and dm-multipath interchangeably to signify the same package. Also note that dm-multipath is the name of the repackaged multipath-tools redistributed under Red Hat in their Advanced Server Linux distribution.