$ sudo mdadm --detail /dev/md0
/dev/md0:
           Version : 1.2
     Creation Time : Sat Jan  9 16:36:18 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 : 3
     Total Devices : 3
       Persistence : Superblock is persistent
       Update Time : Sat Jan  9 16:36:21 2021
             State : clean, resyncing
    Active Devices : 3
   Working Devices : 3
    Failed Devices : 0
     Spare Devices : 0
Consistency Policy : resync
     Resync Status : 23% complete
              Name : dev-machine:0  (local to host dev-machine)
              UUID : e0e5d514:d2294825:45d9f09c:db485a0c
            Events : 3
    Number   Major   Minor   RaidDevice State
       0     252        0        0      active sync   /dev/rd0
       1       8       34        1      active sync writemostly   /dev/sdc2
       2       8       50        2      active sync writemostly   /dev/sdd2