Device-mapper is a Linux kernel framework that maps virtual block devices to physical storage.
Targets in device-mapper are plugsins that define how device-mapper handles IO for a region of a virtual block device.
thin-pool
Target that provides:
- thin provisioning: you can create virtual block devices that appear to have a certain size (e.g., 100GB) but only consume actual storage for the data actually written. The pool allocates blocks on-demand
- copy-on-write snapshots: the snapshot and original share all their data until something is modified, at which point only the changed blocks are copied.