Unable to Mount RAID1 md0 - wrong fs type, bad option, bad superblock on /dev/md0, missing codepage or helper program, or other error

Question

I've created a RAID 1 using mdadm as below however I am having problems mounting it...

sudo mdadm --create --verbose /dev/md0 --level=1 --raid-devices=2 /dev/sdb /dev/sdc
mdadm: /dev/sdb appears to be part of a raid array:
       level=raid1 devices=2 ctime=Sun Nov  5 20:36:10 2017
mdadm: Note: this array has metadata at the start and
    may not be suitable as a boot device.  If you plan to
    store '/boot' on this device please ensure that
    your boot-loader understands md/v1.x metadata, or use
    --metadata=0.90
mdadm: size set to 625000768K
mdadm: automatically enabling write-intent bitmap on large array
Continue creating array? yes
mdadm: Defaulting to version 1.2 metadata
mdadm: array /dev/md0 started.

sudo mdadm --examine --scan --config=/etc/mdadm/mdadm.conf
ARRAY /dev/md/0  metadata=1.2 UUID=1e236272:3e68ea7b:fab6ba77:eb211675 name=SPCURTIS81-projSERV:0

However when I try to mount the array, I'm getting the following error...

sudo mount /dev/md0 /home/ste/mnt/
mount: /home/ste/mnt: wrong fs type, bad option, bad superblock on /dev/md0, missing codepage or helper program, or other error.

I've Google'd and searched on here but I'm struggling to find anything which I understand to relate directly to this.

Some of the following info may or may not however be of use...

lsblk

NAME           MAJ:MIN RM   SIZE RO TYPE  MOUNTPOINT
sda              8:0    0 465.8G  0 disk
├─sda1           8:1    0  18.6G  0 part  /
├─sda2           8:2    0     1K  0 part
├─sda5           8:5    0 442.4G  0 part  /home
└─sda6           8:6    0   4.8G  0 part
  └─cryptswap1 253:0    0   4.8G  0 crypt
sdb              8:16   0 596.2G  0 disk
└─md0            9:0    0   596G  0 raid1
sdc              8:32   0 596.2G  0 disk
└─md0            9:0    0   596G  0 raid1

fsck Same result for both sdb & sdc - fsck from util-linux 2.30.1

cat /proc/mdstat

Personalities : [linear] [multipath] [raid0] [raid1] [raid6] [raid5] [raid4] [raid10]
md0 : active raid1 sdc[1] sdb[0]
      625000768 blocks super 1.2 [2/2] [UU]
      [===>.................]  resync = 18.5% (116140608/625000768) finish=78.1min speed=108513K/sec
      bitmap: 5/5 pages [20KB], 65536KB chunk

Answer 1

You have to make a file system on your array. The raw array is just a block device, which can hold any kind of file system, or non file system data.

To make a filesystem, you can issue sudo mkfs.ext4 /dev/md0 to make a new filesystem with EXT4 (one of the more popular file systems; works great for all round use.

After you've made a file system you can mount it using the command sudo mount /dev/md0 /home/ste/mnt/