Jtdcftul

I am running a server that connects to a multi-drive disk array, It is connected in a dual path configuration. Because of this, all of the drives show up twice.

I suffered a power outage and now the array is not assembling. I do however have the original commands I use. When I have attempted to assemble it says that there is no superblock.

mdadm: No super block found on /dev/mapper/35000c500415cbb87 (Expected magic a92b4efc, got 00000000)

mdadm: no RAID superblock on /dev/mapper/35000c500415cbb87

I have two questions:

1. Is it possible to reassemble the array at this point or is any data lost?


2. How should I do this properly to avoid this in the future.

Initial commands run:

-Attempted to setup array, realized that I had twice as many drives.
-Learned about multipath
-Built a config that included the excluded the non-multipath drivers (see below)
- Created a Raid6 array using the /dev/mapper/drives.
Commands:

sudo mdadm --create --verbose /dev/md0 --level=6 --raid-devices=12 dev/mapper/35000c500415cbb87 /dev/mapper/35000c500415cbbef /dev/mapper/35000c500415cfea3 /dev/mapper/35000c500415d0e3b /dev/mapper/35000c500415d6e3b /dev/mapper/35000c500415e456b /dev/mapper/35000c500415e4e5f /dev/mapper/35000c500415e8223 /dev/mapper/35000c500415ee867 /dev/mapper/35000c5004160b2df /dev/mapper/35000c5004160b6bb /dev/mapper/35000c50041611daf 



sudo mdadm -A /dev/mapper/35000c500415cbb87 /dev/mapper/35000c500415cbbef /dev/mapper/35000c500415cfea3 /dev/mapper/35000c500415d0e3b /dev/mapper/35000c500415d6e3b /dev/mapper/35000c500415e456b /dev/mapper/35000c500415e4e5f /dev/mapper/35000c500415e8223 /dev/mapper/35000c500415ee867 /dev/mapper/35000c5004160b2df /dev/mapper/35000c5004160b6bb /dev/mapper/35000c50041611daf



sudo mkfs.ext4 -F /dev/md0

sudo mkdir -p /mnt/md0

sudo mount /dev/md0 /mnt/md0

sudo mdadm --detail --scan | sudo tee -a /etc/mdadm/mdadm.conf

sudo update-initramfs -u

At that point, I setup folders and started using the drive, until the power outage shut it down. Upon restart, I cannot get it to reassemble.

/etc/multipath.conf

defaults {

        user_friendly_names no

}

blacklist {

    wwid "600508e000000000997d2e0655fb5108"

    wwid "5002538d408c9715"

    device {

        vendor "Dell    "

        product "Virtual Disk    "

    }

}

/etc/mdadm/mdadm.conf

# wildcards if desired.

#DEVICE partitions containers



DEVICE /dev/mapper/35000c500415cbb87

DEVICE /dev/mapper/35000c500415cbbef

DEVICE /dev/mapper/35000c500415cfea3

DEVICE /dev/mapper/35000c500415d0e3b

DEVICE /dev/mapper/35000c500415d6e3b

DEVICE /dev/mapper/35000c500415e456b

DEVICE /dev/mapper/35000c500415e4e5f

DEVICE /dev/mapper/35000c500415e8223

DEVICE /dev/mapper/35000c500415ee867

DEVICE /dev/mapper/35000c5004160b2df

DEVICE /dev/mapper/35000c5004160b6bb

DEVICE /dev/mapper/35000c50041611daf





# 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



# This configuration was auto-generated on Wed, 25 Jul 2018 23:01:52 +0000 by mkconf

ARRAY /dev/md0 metadata=1.2 name=media:0 UUID=5cfbe80c:d11c6b57:4beaff64:ed3bc6dd