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I messed up. I just went through reinstalling and recovering an array yesterday. The array was working just fine. However, I was having a problem with an external drive wanting to be booted by the BIOS. I went into the BIOS and loaded the default settings.

Now my system doesn't see the RAID drive, and the command that pieced it together yesterday, sudo mdadm --assemble --scan is not finding the drive. sudo mdadm --assemble /dev/md0 /dev/sdb /dev/sdc /dev/sdd /dev/sde is not working either.

Here's the main crutch of my question: If I recreate the array (and not try to recreate the ext4 partition on the array) do I run any risk of losing data?

Edit:I'm considering running mdadm --create /dev/md0 -v --assume-clean --level=raid10 --raid-device=4 /dev/sd[bcde] and then if i can't mount the partition I plan on using something like testdisk to search for one. Any advice would be appreciated.

Edit 2: I haven't done anything yet. Here's more information:

Results of ls -la /dev/disk/by-uuid

lrwxrwxrwx 1 root root 10 Oct 15 11:57 40cec677-2f33-494b-998a-b4404203eda2  ../../sda1
lrwxrwxrwx 1 root root 10 Oct 15 11:57 4e4c4847-93ae-4a01-b4af-a8b7bfae5afc -> ../../sda5

Results of mdadm.conf

# Please refer to mdadm.conf(5) for information about this file.
#

# by default (built-in), scan all partitions (/proc/partitions) and all
# containers for MD superblocks. alternatively, specify devices to scan, using
# wildcards if desired.
#DEVICE partitions containers

# auto-create devices with Debian standard permissions
CREATE owner=root group=disk mode=0660 auto=yes

# automatically tag new arrays as belonging to the local system
HOMEHOST <system>

# instruct the monitoring daemon where to send mail alerts
MAILADDR root

# definitions of existing MD arrays
ARRAY /dev/md/0 metadata=1.2 UUID=07e0921a:529e8434:58ca9dea:8e950b2e name=plex$

# This file was auto-generated on Thu, 13 Oct 2016 16:38:46 -0400
# by mkconf $Id$

Please let me know if there's any other information I can provide to help.

Edit 3: running the command in edit 1, I received the following:

root@plex:~# mdadm --create /dev/md0 -v --assume-clean --level=raid10 --raid-device=4 /dev/sd[bcde]
mdadm: layout defaults to n2
mdadm: layout defaults to n2
mdadm: chunk size defaults to 512K
mdadm: /dev/sdb appears to be part of a raid array:
    level=raid0 devices=0 ctime=Wed Dec 31 19:00:00 1969
mdadm: partition table exists on /dev/sdb but will be lost or
       meaningless after creating array
mdadm: /dev/sdc appears to be part of a raid array:
    level=raid0 devices=0 ctime=Wed Dec 31 19:00:00 1969
mdadm: partition table exists on /dev/sdc but will be lost or
       meaningless after creating array
mdadm: /dev/sdd appears to be part of a raid array:
    level=raid0 devices=0 ctime=Wed Dec 31 19:00:00 1969
mdadm: partition table exists on /dev/sdd but will be lost or
       meaningless after creating array
mdadm: /dev/sde appears to be part of a raid array:
    level=raid0 devices=0 ctime=Wed Dec 31 19:00:00 1969
mdadm: partition table exists on /dev/sde but will be lost or
       meaningless after creating array
mdadm: size set to 4883639296K
Continue creating array? 

I chose no and am awaiting advice. At least mdadm can see my raid array, even if it can't automatically assemble it.

Edit 4: Just more information:

root@plex:~# mdadm --query /dev/sd[bcde]
/dev/sdb: is not an md array
/dev/sdb: device 0 in 0 device unknown raid0 array.  Use mdadm --examine for more detail.
/dev/sdc: is not an md array
/dev/sdc: device 0 in 0 device unknown raid0 array.  Use mdadm --examine for more detail.
/dev/sdd: is not an md array
/dev/sdd: device 0 in 0 device unknown raid0 array.  Use mdadm --examine for more detail.
/dev/sde: is not an md array
/dev/sde: device 0 in 0 device unknown raid0 array.  Use mdadm --examine for more detail.

And the more details:

root@plex:~# mdadm --examine /dev/sd[bcde]
/dev/sdb:
   MBR Magic : aa55
Partition[0] :   4294967295 sectors at            1 (type ee)
/dev/sdc:
   MBR Magic : aa55
Partition[0] :   4294967295 sectors at            1 (type ee)
/dev/sdd:
   MBR Magic : aa55
Partition[0] :   4294967295 sectors at            1 (type ee)
/dev/sde:
   MBR Magic : aa55
Partition[0] :   4294967295 sectors at            1 (type ee)
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Okay, here's what got it going.

Recreate the array. Ignore warning about losing data.

Use testdisk to search for and find partition.

Reboot

Mount and we're good. :)

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