Clonezilla
Clonezilla is the disk copying tool used to replicate the drives across slave nodes. See Clonezilla Step-by-Step guides for a how-to guide on disk-to-disk cloning. Inside Minotaur's server rack is an external HDD and a USB. Clonezilla is on the USB, and a copy from a slave node is on the HDD. Reboot a working (and up to date) node with the Clonezilla USB and copy its drive (sda#) to the external HDD (sdb#). The External HDD is much larger than the slave node therefore select Expert-cloning method and under advanced options select "use the partition from the image." Then boot the failed node using Clonezilla and perform the reverse operation, copying the external HDD (sdb#) to the internal drive (sda#). Copying may take a while, up to 2Hrs. Because the target drive is now smaller than the source drive, select the expert method and highlight the option "[*] -icds Skip checking destination partition size before creating partition table." Make sure "use the partition table from the image" is also selected.