mdadm 3.3.2 Description:
mdadm is an open source, small, fast and free command-line utility implemented in C and designed for maintaining, creating, and monitoring Linux "md" device arrays, popularly known as software RAID. A minimal initramfs for assembling md arrays can be created using three files and one directory. These are the /bin directory, the /bin/mdadm statically linked mdadm binary, the /bin/busybox statically linked busybox binary, the /bin/sh hard link to /bin/busybox, and /init, a shell script which calls mdadm appropriately. Default command-line options include the ability to create a new array from unused devices, assemble a previously created array, to create or assemble an array without metadata, to make changes to an existing array, to report on or modify several md related devices, to reshape or resize an active array, to remove or add a device from/to an array, as well as to monitor a single or multiple arrays.