Changes

{{Note box| the addition of another drive is restricted to a RAID 1 degraded, i.e. when the system has been installed with a single drive (/dev/hda and /dev/hdc or their SATA equivalent). The addition of a third drive to a RAID 1 '''(i.e. a spare)''' is not recognized by the system. therefore you need to use the '''mdadm''' command line}}

{{Note box| the addition of another drive is restricted to a RAID 1 degraded, i.e. when the system has been installed with a single drive (/dev/hda and /dev/hdc or their SATA equivalent). The addition of a third drive to a RAID 1 '''(i.e. a spare)''' is not recognized by the system. therefore you need to use the '''mdadm''' command line}}

{{Note box|I suppose the system is installed with a Raid1 functional on two disk sda and sdb and you want to add another disk sdc as a spare (for use automatically if one disk of the array will fail)}}

{{Note box|I suppose the system is installed with a Raid1 functional on two disk sda and sdb and you want to add another disk sdc as a spare (for use automatically if one disk of the array will fail).This howto can be adapted to other types of Raid as long as you want to add a spare disk.}}

first we need to give to sdc the same table of partition as sda or sdb

first we need to give to sdc the same table of partition as sda or sdb