RAID 1 is composed of an exact copy (or mirror) of a set of data on two or more disks; a classic RAID 1 mirrored pair has two disks. When using a RAID 1 volume, information is written to a first drive and to a second (or "mirror") drive simultaneously. It is not necessary to remove any information from the remaining hard drive if one of the drives in the mirror volume fails. For more explanation on this video: https://www.linuxhelp.com/how-to-configure-raid-1-on-rocky-linux-8-6