$ sudo mdadm --detail /dev/md0 /dev/md0: Version : 1.2 Creation Time : Sat Jan 9 16:32:43 2021 Raid Level : raid1 Array Size : 2094080 (2045.00 MiB 2144.34 MB) Used Dev Size : 2094080 (2045.00 MiB 2144.34 MB) Raid Devices : 2 Total Devices : 2 Persistence : Superblock is persistent Update Time : Sat Jan 9 16:32:54 2021 State : clean Active Devices : 2 Working Devices : 2 Failed Devices : 0 Spare Devices : 0 Consistency Policy : resync Name : dev-machine:0 (local to host dev-machine) UUID : 79387934:aaaad032:f56c6261:de230a86 Events : 17 Number Major Minor RaidDevice State 0 252 0 0 active sync /dev/rd0 1 8 34 1 active sync writemostly /dev/sdc2