mdadm --detail /dev/md3
/dev/md3:
           Version : 1.2
     Creation Time : ...
        Raid Level : raid1
        Array Size : 1953381440 (1862.89 GiB 2000.26 GB)
     Used Dev Size : 1953381440 (1862.89 GiB 2000.26 GB)
      Raid Devices : 2
     Total Devices : 2
       Persistence : Superblock is persistent

     Intent Bitmap : Internal

       Update Time : Fri Nov 15 17:03:11 2019
             State : clean, resyncing
    Active Devices : 2
   Working Devices : 2
    Failed Devices : 0
     Spare Devices : 0

Consistency Policy : bitmap

     Resync Status : 1% complete

              Name : ....:3  (local to host ....)
              UUID : ....
            Events : 46

    Number   Major   Minor   RaidDevice State
       0       8        1        0      active sync   /dev/sda1
       1       8       17        1      active sync   /dev/sdb1