for x in /dev/sd[cef]1 ; do echo $x ; mdadm -E $x ; done

/dev/sdb1
/dev/sdb1:
          Magic : a92b4efc
        Version : 1.2
    Feature Map : 0x5
     Array UUID : e410e68d:76460b65:69c056c0:d2645d55
           Name : nas-server:0  (local to host nas-server)
  Creation Time : Fri Dec  1 02:10:06 2017
     Raid Level : raid5
   Raid Devices : 4

 Avail Dev Size : 7813771264 (3725.90 GiB 4000.65 GB)
     Array Size : 11720656896 (11177.69 GiB 12001.95 GB)
    Data Offset : 262144 sectors
   Super Offset : 8 sectors
   Unused Space : before=262056 sectors, after=0 sectors
          State : active
    Device UUID : f4490b9f:475aca83:2ff93d65:a4fabf8c

Internal Bitmap : 8 sectors from superblock
  Reshape pos'n : 4021168128 (3834.88 GiB 4117.68 GB)
  Delta Devices : 1 (3->4)

    Update Time : Sun Dec  3 13:34:43 2017
  Bad Block Log : 512 entries available at offset 72 sectors
       Checksum : d1b15eed - correct
         Events : 28155

         Layout : left-symmetric
     Chunk Size : 512K

   Device Role : Active device 0
   Array State : AAA. ('A' == active, '.' == missing, 'R' == replacing)
/dev/sdd1
/dev/sdd1:
          Magic : a92b4efc
        Version : 1.2
    Feature Map : 0x5
     Array UUID : e410e68d:76460b65:69c056c0:d2645d55
           Name : nas-server:0  (local to host nas-server)
  Creation Time : Fri Dec  1 02:10:06 2017
     Raid Level : raid5
   Raid Devices : 4

 Avail Dev Size : 7813771264 (3725.90 GiB 4000.65 GB)
     Array Size : 11720656896 (11177.69 GiB 12001.95 GB)
    Data Offset : 262144 sectors
   Super Offset : 8 sectors
   Unused Space : before=262056 sectors, after=0 sectors
          State : active
    Device UUID : eb679765:5771cc1a:651f5a86:e166424b

Internal Bitmap : 8 sectors from superblock
  Reshape pos'n : 4021168128 (3834.88 GiB 4117.68 GB)
  Delta Devices : 1 (3->4)

    Update Time : Sun Dec  3 13:34:43 2017
  Bad Block Log : 512 entries available at offset 72 sectors
       Checksum : ede2668 - correct
         Events : 28155

         Layout : left-symmetric
     Chunk Size : 512K

   Device Role : Active device 1
   Array State : AAA. ('A' == active, '.' == missing, 'R' == replacing)
/dev/sde1
/dev/sde1:
          Magic : a92b4efc
        Version : 1.2
    Feature Map : 0x7
     Array UUID : e410e68d:76460b65:69c056c0:d2645d55
           Name : nas-server:0  (local to host nas-server)
  Creation Time : Fri Dec  1 02:10:06 2017
     Raid Level : raid5
   Raid Devices : 4

 Avail Dev Size : 7813771264 (3725.90 GiB 4000.65 GB)
     Array Size : 11720656896 (11177.69 GiB 12001.95 GB)
    Data Offset : 262144 sectors
   Super Offset : 8 sectors
Recovery Offset : 2680909424 sectors
   Unused Space : before=262056 sectors, after=0 sectors
          State : active
    Device UUID : 2c5c510d:3ddd9cb3:85782829:cdce1b89

Internal Bitmap : 8 sectors from superblock
  Reshape pos'n : 4021168128 (3834.88 GiB 4117.68 GB)
  Delta Devices : 1 (3->4)

    Update Time : Sun Dec  3 13:34:43 2017
  Bad Block Log : 512 entries available at offset 72 sectors
       Checksum : cfdbb60f - correct
         Events : 28155

         Layout : left-symmetric
     Chunk Size : 512K

   Device Role : Active device 2
   Array State : AAA. ('A' == active, '.' == missing, 'R' == replacing)