$ cat /proc/mdstat [...] md2 : active raid1 sdd1[1] sdc1[0] 1953382464 blocks super 1.2 [2/2] [UU] bitmap: 15/15 pages [60KB], 65536KB chunk [...] $ mdadm --detail /dev/md2 /dev/md2: Version : 1.2 Creation Time : Fri Nov 11 16:50:43 2016 Raid Level : raid1 Array Size : 1953382464 (1862.89 GiB 2000.26 GB) [...] Number Major Minor RaidDevice State 0 8 33 0 active sync /dev/sdc1 1 8 49 1 active sync /dev/sdd1