Accidental Reboot / Shutdown Causes Errors In The Hard Drive

I accidentally pressed the hardware reset because it's too close to the headphone jacks. I've got big fingers what can I say. So it's a couple of seconds later that I noticed that the computer (the monitor) has restarted. Except that the initial restart sequence is throwing me to a console with a bad ata status:DRDY message. I've seen this before. It's a bad shutdown for one or more of the hard drives / raid device.
I checked the status of the RAID device and confirmed it. I've got an inactive array. So I issued:

#mdadm /dev/md0 --stop

to stop the array and restart it with:

#mdadm --assemble /dev/md0 /dev/sdb1 /dev/sdc1 /dev/sdd1

but no go, so again i tried this:

#mdadm --assemble --force /dev/md0 /dev/sdb1 /dev/sdc1 /dev/sdd1

I check the status of the array after I started it.

#mdadm --detail /dev/md0

root@desktop:~# mdadm --detail /dev/md0
/dev/md0:
        Version : 1.2
  Creation Time : Tue Sep  6 02:59:21 2016
     Raid Level : raid5
     Array Size : 1953260544 (1862.77 GiB 2000.14 GB)
  Used Dev Size : 976630272 (931.39 GiB 1000.07 GB)
   Raid Devices : 3
  Total Devices : 2
    Persistence : Superblock is persistent

  Intent Bitmap : Internal

    Update Time : Sun Dec  4 22:59:12 2016
          State : clean, degraded
 Active Devices : 2
Working Devices : 2
 Failed Devices : 0
  Spare Devices : 0

         Layout : left-symmetric
     Chunk Size : 512K

           Name : desktop:0  (local to host desktop)
           UUID : e3284314:1258cac3:1b6c243c:748be2fe
         Events : 2849

    Number   Major   Minor   RaidDevice State
       0       8       17        0      active sync   /dev/sdb1
       1       8       33        1      active sync   /dev/sdc1
       4       0        0        4      removed

One of the devices comprising this array is removed. Maybe due to corrupt data or something else. I figured i could do more if I reboot with this degraded array into my desktop. So I did. I used the Gnome SMART checker (it's what I call it). Refreshed the status and the devices checks out.

So figuring out that the device is not really bad (according to SMART). I added it back to the array with:

#mdadm --manage --add /dev/md0 /dev/sdd1

I checked the status of the array with:

#mdadm --detail /dev/md0

/dev/md0:
        Version : 1.2
  Creation Time : Tue Sep  6 02:59:21 2016
     Raid Level : raid5
     Array Size : 1953260544 (1862.77 GiB 2000.14 GB)
  Used Dev Size : 976630272 (931.39 GiB 1000.07 GB)
   Raid Devices : 3
  Total Devices : 3
    Persistence : Superblock is persistent

  Intent Bitmap : Internal

    Update Time : Sun Dec  4 23:11:48 2016
          State : clean, degraded, recovering
 Active Devices : 2
Working Devices : 3
 Failed Devices : 0
  Spare Devices : 1

         Layout : left-symmetric
     Chunk Size : 512K

 Rebuild Status : 4% complete

           Name : desktop:0  (local to host desktop)
           UUID : e3284314:1258cac3:1b6c243c:748be2fe
         Events : 2853

    Number   Major   Minor   RaidDevice State
       0       8       17        0      active sync   /dev/sdb1
       1       8       33        1      active sync   /dev/sdc1
       3       8       49        2      spare rebuilding   /dev/sdd1

All I have to do now is wait for it to rebuild the device back to the array.

/dev/md0:
        Version : 1.2
  Creation Time : Tue Sep  6 02:59:21 2016
     Raid Level : raid5
     Array Size : 1953260544 (1862.77 GiB 2000.14 GB)
  Used Dev Size : 976630272 (931.39 GiB 1000.07 GB)
   Raid Devices : 3
  Total Devices : 3
    Persistence : Superblock is persistent

  Intent Bitmap : Internal

    Update Time : Sun Dec  4 23:14:22 2016
          State : clean
 Active Devices : 3
Working Devices : 3
 Failed Devices : 0
  Spare Devices : 0

         Layout : left-symmetric
     Chunk Size : 512K

           Name : desktop:0  (local to host desktop)
           UUID : e3284314:1258cac3:1b6c243c:748be2fe
         Events : 2890

    Number   Major   Minor   RaidDevice State
       0       8       17        0      active sync   /dev/sdb1
       1       8       33        1      active sync   /dev/sdc1
       3       8       49        2      active sync   /dev/sdd1

It took just 10 minutes.