/dev/md0:
        Version : 1.2
  Creation Time : Wed Jan 20 13:15:51 2016
     Raid Level : raid1
     Array Size : 19514240 (18.61 GiB 19.98 GB)
  Used Dev Size : 19514240 (18.61 GiB 19.98 GB)
   Raid Devices : 2
  Total Devices : 3
    Persistence : Superblock is persistent

    Update Time : Fri Jun 23 15:35:39 2017
          State : clean, degraded 
 Active Devices : 1
Working Devices : 2
 Failed Devices : 0
  Spare Devices : 1

           Name : root:0
           UUID : 6388f9ee:94361081:3d5b8391:3d963add
         Events : 1476

    Number   Major   Minor   RaidDevice State
       0       8        3        0      active sync   /dev/sda3
       1       0        0        1      removed

       1       8       19        -      spare   /dev/sdb3