sudo mdadm -Q /dev/sda --examine
/dev/sda:
          Magic : Intel Raid ISM Cfg Sig.
        Version : 1.0.00
    Orig Family : 4bde71b4
         Family : 4bde71b4
     Generation : 00000f52
     Attributes : All supported
           UUID : 4b914255:153bbe5c:ba75320a:feb67d6b
       Checksum : e49bef6c correct
    MPB Sectors : 1
          Disks : 2
   RAID Devices : 1

[RAID0IMSVolume]:
           UUID : a8702b4d:3d59e93e:af849228:0cec4694
     RAID Level : 0
        Members : 2
          Slots : [_U]
    Failed disk : 0
      This Slot : ?
     Array Size : 1000218624 (476.94 GiB 512.11 GB)
   Per Dev Size : 500109576 (238.47 GiB 256.06 GB)
  Sector Offset : 0
    Num Stripes : 1953552
     Chunk Size : 128 KiB
       Reserved : 0
  Migrate State : idle
      Map State : normal
    Dirty State : clean

  Disk00 Serial : P02430111202
          State : active failed
             Id : 00000000
    Usable Size : 500111886 (238.47 GiB 256.06 GB)

  Disk01 Serial : P02430111218
          State : active
             Id : 00000001
    Usable Size : 500111886 (238.47 GiB 256.06 GB)