OMV OS Drive Failed, How to recover RAID

root@snowdon:/# mdadm --stop /dev/md127
mdadm: stopped /dev/md127
root@snowdon:/# mdadm --assemble --force --verbose /dev/md126 /dev/sd[bcd]
mdadm: looking for devices for /dev/md126
mdadm: /dev/sdb is identified as a member of /dev/md126, slot 2.
mdadm: /dev/sdc is identified as a member of /dev/md126, slot 1.
mdadm: /dev/sdd is identified as a member of /dev/md126, slot 0.
mdadm: added /dev/sdc to /dev/md126 as 1
mdadm: added /dev/sdb to /dev/md126 as 2
mdadm: added /dev/sdd to /dev/md126 as 0
mdadm: /dev/md126 has been started with 3 drives.
root@snowdon:/#

root@snowdon:/# cat /etc/fstab
# /etc/fstab: static file system information.
#
# Use 'blkid' to print the universally unique identifier for a
# device; this may be used with UUID= as a more robust way to name devices
# that works even if disks are added and removed. See fstab(5).
#
# <file system> <mount point> <type> <options> <dump> <pass>
# / was on /dev/sda1 during installation
UUID=38f45487-8693-4b71-ad79-eb3d2797380b / ext4 errors=remount-ro 0 1
# swap was on /dev/sda5 during installation
UUID=e853670d-1950-4a3a-bff8-79afe94905b2 none swap sw 0 0
/dev/sr0 /media/cdrom0 udf,iso9660 user,noauto 0 0
# >>> [openmediavault]
# <<< [openmediavault]

root@snowdon:/# blkid
/dev/sdb: UUID="5400d348-9300-2dd3-89c8-5e22c933904c" UUID_SUB="3ba9adbf-131c-907a-c765-ced561cac6b3" LABEL="snowdon:Nixdy" TYPE="linux_raid_member"
/dev/sdd: UUID="5400d348-9300-2dd3-89c8-5e22c933904c" UUID_SUB="a082aebb-868f-a1fb-34a2-4ad00d3433fa" LABEL="snowdon:Nixdy" TYPE="linux_raid_member"
/dev/sda1: UUID="38f45487-8693-4b71-ad79-eb3d2797380b" TYPE="ext4" PARTUUID="00096f5f-01"
/dev/sda5: UUID="e853670d-1950-4a3a-bff8-79afe94905b2" TYPE="swap" PARTUUID="00096f5f-05"
/dev/sdc: UUID="5400d348-9300-2dd3-89c8-5e22c933904c" UUID_SUB="4814b415-3105-bae1-fe1b-6e83251226e6" LABEL="snowdon:Nixdy" TYPE="linux_raid_member"

root@snowdon:/# cat /proc/mdstat
Personalities : [raid6] [raid5] [raid4]
md126 : active (auto-read-only) raid5 sdd[0] sdb[2] sdc[1]
3906766848 blocks super 1.2 level 5, 512k chunk, algorithm 2 [3/3] [UUU]
bitmap: 0/15 pages [0KB], 65536KB chunk

unused devices: <none>

still can't see the volumes in shared folders add

dropdown is blank

oh dear

root@snowdon:/# mdadm --readwrite /dev/md126
mdadm: error opening /dev/md126: No such file or directory
root@snowdon:/# blkid
/dev/sdb: UUID="5400d348-9300-2dd3-89c8-5e22c933904c" UUID_SUB="3ba9adbf-131c-907a-c765-ced561cac6b3" LABEL="snowdon:Nixdy" TYPE="linux_raid_member"
/dev/sdd: UUID="5400d348-9300-2dd3-89c8-5e22c933904c" UUID_SUB="a082aebb-868f-a1fb-34a2-4ad00d3433fa" LABEL="snowdon:Nixdy" TYPE="linux_raid_member"
/dev/sdc: UUID="5400d348-9300-2dd3-89c8-5e22c933904c" UUID_SUB="4814b415-3105-bae1-fe1b-6e83251226e6" LABEL="snowdon:Nixdy" TYPE="linux_raid_member"
/dev/sda1: UUID="38f45487-8693-4b71-ad79-eb3d2797380b" TYPE="ext4" PARTUUID="00096f5f-01"
/dev/sda5: UUID="e853670d-1950-4a3a-bff8-79afe94905b2" TYPE="swap" PARTUUID="00096f5f-05"

Re-booted

root@snowdon:/# cat /proc/mdstat
Personalities : [raid6] [raid5] [raid4]
md0 : active (auto-read-only) raid5 sdd[0] sdb[2] sdc[1]
3906766848 blocks super 1.2 level 5, 512k chunk, algorithm 2 [3/3] [UUU]
bitmap: 0/15 pages [0KB], 65536KB chunk

unused devices: <none>
root@snowdon:/# blkid
/dev/sda1: UUID="38f45487-8693-4b71-ad79-eb3d2797380b" TYPE="ext4" PARTUUID="00096f5f-01"
/dev/sda5: UUID="e853670d-1950-4a3a-bff8-79afe94905b2" TYPE="swap" PARTUUID="00096f5f-05"
/dev/sdd: UUID="5400d348-9300-2dd3-89c8-5e22c933904c" UUID_SUB="a082aebb-868f-a1fb-34a2-4ad00d3433fa" LABEL="snowdon:Nixdy" TYPE="linux_raid_member"
/dev/sdc: UUID="5400d348-9300-2dd3-89c8-5e22c933904c" UUID_SUB="4814b415-3105-bae1-fe1b-6e83251226e6" LABEL="snowdon:Nixdy" TYPE="linux_raid_member"
/dev/sdb: UUID="5400d348-9300-2dd3-89c8-5e22c933904c" UUID_SUB="3ba9adbf-131c-907a-c765-ced561cac6b3" LABEL="snowdon:Nixdy" TYPE="linux_raid_member"

I do have another spare hard drive that I could add to the system. I will try photorec though never used before. Ryecoaaron thank you for your help trying to get this fixed really appreciate it.

root@snowdon:/# sudo apt-get install testdisk
Reading package lists... Done
Building dependency tree
Reading state information... Done
The following NEW packages will be installed:
testdisk
0 upgraded, 1 newly installed, 0 to remove and 0 not upgraded.
Need to get 359 kB of archives.
After this operation, 1,242 kB of additional disk space will be used.
WARNING: The following packages cannot be authenticated!
testdisk
Install these packages without verification? [y/N] Y
Err http://ftp.uk.debian.org/debian/ jessie/main testdisk amd64 6.14-3+b3
Something wicked happened resolving 'ftp.uk.debian.org:http' (-5 - No address associated with hostname)
E: Failed to fetch http://ftp.uk.debian.org/debia…tdisk_6.14-3+b3_amd64.deb Something wicked happened resolving 'ftp.uk.debian.org:http' (-5 - No address associated with hostname)

E: Unable to fetch some archives, maybe run apt-get update or try with --fix-missing?
root@snowdon:/#

Can't download