I am trying to recover data from a MyBookLiveDuo 3TB*2 RAID1 setup, which is not responding to http/ssh access. I pulled one drive out of the enclosure and attached it via SATA to a Linux laptop. I have run the following.Dmesg says it is /dev/sdc:[125141.929807] ata4: exception Emask 0x10 SAct 0x0 SErr 0x4040000 action 0xe frozen[125141.929811] ata4: irq_stat 0x00000040, connection status changed[125141.929813] ata4: SError: { CommWake DevExch }[125141.929827] ata4: hard resetting link[125147.695101] ata4: link is slow to respond, please be patient (ready=0)[125151.729658] ata4: SATA link up 1.5 Gbps (SStatus 113 SControl 300)[125151.909228] ata4.00: ATA-9: WDC WD30EZRX-00D8PB0, 80.00A80, max UDMA/133[125151.909231] ata4.00: 5860533168 sectors, multi 0: LBA48 NCQ (depth 31/32), AA[125151.909888] ata4.00: configured for UDMA/133[125151.925597] ata4: EH complete[125151.925652] scsi 3:0:0:0: Direct-Access     ATA      WDC WD30EZRX-00D 0A80 PQ: 0 ANSI: 5[125151.925828] sd 3:0:0:0: [sdc] 5860533168 512-byte logical blocks: (3.00 TB/2.72 TiB)[125151.925830] sd 3:0:0:0: [sdc] 4096-byte physical blocks[125151.925833] sd 3:0:0:0: Attached scsi generic sg2 type 0[125151.925971] sd 3:0:0:0: [sdc] Write Protect is off[125151.925973] sd 3:0:0:0: [sdc] Mode Sense: 00 3a 00 00[125151.925995] sd 3:0:0:0: [sdc] Write cache: enabled, read cache: enabled, doesn't support DPO or FUA[125152.002603]  sdc: sdc1 sdc2 sdc3 sdc4[125152.003134] sd 3:0:0:0: [sdc] Attached SCSI disk[125152.220477] md: bind<sdc4>[125152.232731] md: bind<sdc3>[125152.233892] md/raid1:md126: active with 1 out of 2 mirrors[125152.233912] md126: detected capacity change from 0 to 512741376[125152.234269]  md126: unknown partition tableTrying to mount sdc4 directly does not work:$ sudo mount /dev/sdc4 /home/xxx/wdc -t automount: unknown filesystem type 'linux_raid_member'Mdstat shows only sdc3 as active, but sdc4 as inactive:$ sudo cat /proc/mdstatPersonalities : [linear] [raid1] md126 : active (auto-read-only) raid1 sdc3[2]      500724 blocks super 1.0 [2/1] [_U]md127 : inactive sdc4[0](S)      2925750264 blocks super 1.0unused devices: <none>Parted shows missing filesystem for sdc4 :$ sudo parted -lModel: ATA WDC WD30EZRX-00D (scsi)Disk /dev/sdc: 3001GBSector size (logical/physical): 512B/4096BPartition Table: gptNumber  Start   End     Size    File system  Name     Flags 3      15.7MB  528MB   513MB                primary  raid 1      528MB   2576MB  2048MB  ext3         primary  raid 2      2576MB  4624MB  2048MB  ext3         primary  raid 4      4624MB  3001GB  2996GB               primary  raidGdisk v (verify) does not find any problems though:$ sudo gdisk /dev/sdcGPT fdisk (gdisk) version 0.8.8Partition table scan:  MBR: protective  BSD: not present  APM: not present  GPT: presentFound valid GPT with protective MBR; using GPT.Command (? for help): pDisk /dev/sdc: 5860533168 sectors, 2.7 TiBLogical sector size: 512 bytesDisk identifier (GUID): FA502922-25C1-4759-AAF8-3D1DDA73F5C4Partition table holds up to 128 entriesFirst usable sector is 34, last usable sector is 5860533134Partitions will be aligned on 2048-sector boundariesTotal free space is 31597 sectors (15.4 MiB)Number  Start (sector)    End (sector)  Size       Code  Name   1         1032192         5031935   1.9 GiB     FD00  primary   2         5031936         9031679   1.9 GiB     FD00  primary   3           30720         1032191   489.0 MiB   FD00  primary   4         9031680      5860532223   2.7 TiB     FD00  primaryCommand (? for help): vNo problems found. 31597 free sectors (15.4 MiB) available in 2segments, the largest of which is 30686 (15.0 MiB) in size.Command (? for help): qTrying to assemble and scan only shows /dev/sdc3 as active:$ sudo mdadm --stop /dev/md12[567]mdadm: stopped /dev/md126mdadm: stopped /dev/md127$ sudo cat /proc/mdstatPersonalities : [linear] [raid1] unused devices: <none>$ sudo mdadm --assemble --scanmdadm: /dev/md/MyBookLiveDuo:3 assembled from 1 drive - not enough to start the array.mdadm: /dev/md/MyBookLiveDuo:2 has been started with 1 drive (out of 2).mdadm: /dev/md/MyBookLiveDuo:3 assembled from 1 drive - not enough to start the array.$ sudo cat /proc/mdstatPersonalities : [linear] [raid1] md127 : active raid1 sdc3[2]      500724 blocks super 1.0 [2/1] [_U]unused devices: <none>E2fsck says bad magic number in super-block:$ sudo e2fsck /dev/sdc3e2fsck 1.42.9 (4-Feb-2014)/dev/sdc3 is in use.e2fsck: Cannot continue, aborting.$ sudo e2fsck /dev/sdc4e2fsck 1.42.9 (4-Feb-2014)ext2fs_open2: Bad magic number in super-blocke2fsck: Superblock invalid, trying backup blocks...e2fsck: Bad magic number in super-block while trying to open /dev/sdc4The superblock could not be read or does not describe a valid ext2/ext3/ext4filesystem.  If the device is valid and it really contains an ext2/ext3/ext4filesystem (and not swap or ufs or something else), then the superblockis corrupt, and you might try running e2fsck with an alternate superblock:    e2fsck -b 8193 <device> or    e2fsck -b 32768 <device>$ Trying to mount md127 thinks it is NTFS ???$ sudo mount /dev/md127 /home/xxx/wdc -t autoNTFS signature is missing.Failed to mount '/dev/md127': Invalid argumentThe device '/dev/md127' doesn't seem to have a valid NTFS.Maybe the wrong device is used? Or the whole disk instead of apartition (e.g. /dev/sda, not /dev/sda1)? Or the other way around?Any suggestion on how to proceed further to be able to mount /dev/sdc4 and recover data ? EDIT 1: Output from examine sdc4 is below. It says RAID level = linear.$ sudo mdadm --examine /dev/sdc4/dev/sdc4:          Magic : a92b4efc        Version : 1.0    Feature Map : 0x0     Array UUID : 374e689e:3bfd050c:ab0b0dce:2d50f5fd           Name : MyBookLiveDuo:3  Creation Time : Mon Sep 16 14:53:47 2013     Raid Level : linear   Raid Devices : 2 Avail Dev Size : 5851500528 (2790.21 GiB 2995.97 GB)  Used Dev Size : 0   Super Offset : 5851500528 sectors          State : clean    Device UUID : 9096f74b:0a8f2b61:93347be3:6d3b6c1b    Update Time : Mon Sep 16 14:53:47 2013       Checksum : 77aa5963 - correct         Events : 0       Rounding : 0K   Device Role : Active device 0   Array State : AA ('A' == active, '.' == missing)Output from examine sdc3 is below, which mdstat says is active. It says RAID level = RAID1.$ sudo mdadm --examine /dev/sdc3/dev/sdc3:          Magic : a92b4efc        Version : 1.0    Feature Map : 0x0     Array UUID : 7c040c5e:9c30ac6d:e534a129:20457e22           Name : MyBookLiveDuo:2  Creation Time : Wed Dec 31 19:01:40 1969     Raid Level : raid1   Raid Devices : 2 Avail Dev Size : 1001448 (489.07 MiB 512.74 MB)     Array Size : 500724 (489.07 MiB 512.74 MB)   Super Offset : 1001456 sectors          State : clean    Device UUID : 1d9fe3e3:d5ac7387:d9ededba:88ca24a5    Update Time : Sun Jul  3 11:53:31 2016       Checksum : 31589560 - correct         Events : 101   Device Role : Active device 1   Array State : .A ('A' == active, '.' == missing)$ cat /proc/mdstat Personalities : [linear] [multipath] [raid0] [raid1] [raid6] [raid5] [raid4] [raid10] md126 : active (auto-read-only) raid1 sdc3[2]      500724 blocks super 1.0 [2/1] [_U]md127 : inactive sdc4[0](S)      2925750264 blocks super 1.0unused devices: <none>And partitions is:$ cat /proc/partitions major minor  #blocks  name   8        0 1953514584 sda   8        1     102400 sda1   8        2 1953411072 sda2   8       16 1953514584 sdb   8       17     248832 sdb1   8       18          1 sdb2   8       21 1953263616 sdb5 252        0 1953261568 dm-0 252        1 1919635456 dm-1 252        2   33488896 dm-2   8       32 2930266584 sdc   8       33    1999872 sdc1   8       34    1999872 sdc2   8       35     500736 sdc3   8       36 2925750272 sdc4   9      126     500724 md126EDIT 2: (Different RAID disk from another enclosure)Using a good disk from a different WDLiveDuo enclosure, which is configured in same RAID1 way (2*3TB disks), the output of examine for sdc3 and sdc4 shows that both have RAID level = RAID1. So, for the bad disk listed above, sdc3 shows correct RAID level = RAID1, but somehow, sdc4 does not have the correct RAID level configured. Is there a way to change/fix the RAID level to be RAID1 and then will it allow me to load it and get data out of the bad disk ?$ cat /proc/mdstat Personalities : [linear] [multipath] [raid0] [raid1] [raid6] [raid5] [raid4] [raid10] md126 : inactive sdc4[2](S)      2925750136 blocks super 1.0md127 : inactive sdc3[1](S)      500724 blocks super 1.0unused devices: <none>$$ cat /proc/partitions major minor  #blocks  name   8        0 1953514584 sda   8        1     102400 sda1   8        2 1953411072 sda2   8       16 1953514584 sdb   8       17     248832 sdb1   8       18          1 sdb2   8       21 1953263616 sdb5 252        0 1953261568 dm-0 252        1 1919635456 dm-1 252        2   33488896 dm-2   8       32 2930266584 sdc   8       33    1999872 sdc1   8       34    1999872 sdc2   8       35     500736 sdc3   8       36 2925750272 sdc4$$ sudo mdadm --examine /dev/sdc3/dev/sdc3:          Magic : a92b4efc        Version : 1.0    Feature Map : 0x0     Array UUID : 7c040c5e:9c30ac6d:e534a129:20457e22           Name : MyBookLiveDuo:2  Creation Time : Wed Dec 31 19:01:40 1969     Raid Level : raid1   Raid Devices : 2 Avail Dev Size : 1001448 (489.07 MiB 512.74 MB)     Array Size : 500724 (489.07 MiB 512.74 MB)   Super Offset : 1001456 sectors          State : clean    Device UUID : e0963cfc:7ba16214:94e24c90:32988d39    Update Time : Mon Jul  4 13:20:48 2016       Checksum : 412bab99 - correct         Events : 288   Device Role : Active device 1   Array State : AA ('A' == active, '.' == missing)$$ sudo mdadm --examine /dev/sdc4/dev/sdc4:          Magic : a92b4efc        Version : 1.0    Feature Map : 0x0     Array UUID : ac48cc98:1d450838:dd0b0364:61b3168e           Name : MyBookLiveDuo:3  Creation Time : Sat Jul  2 19:57:43 2016     Raid Level : raid1   Raid Devices : 2 Avail Dev Size : 5851500272 (2790.21 GiB 2995.97 GB)     Array Size : 2925750136 (2790.21 GiB 2995.97 GB)   Super Offset : 5851500528 sectors          State : clean    Device UUID : 1233b655:2f5fd745:c1c71658:f05af045    Update Time : Mon Jul  4 13:21:15 2016       Checksum : b83b08dc - correct         Events : 54432   Device Role : Active device 1   Array State : AA ('A' == active, '.' == missing)$$ sudo mdadm --stop /dev/md12[567]mdadm: stopped /dev/md126mdadm: stopped /dev/md127$$ sudo mdadm --assemble --scanmdadm: /dev/md/MyBookLiveDuo:3 has been started with 1 drive (out of 2).mdadm: /dev/md/MyBookLiveDuo:2 has been started with 1 drive (out of 2).$$ cat /proc/mdstat Personalities : [linear] [multipath] [raid0] [raid1] [raid6] [raid5] [raid4] [raid10] md126 : active raid1 sdc3[1]      500724 blocks super 1.0 [2/1] [_U]md127 : active raid1 sdc4[2]      2925750136 blocks super 1.0 [2/1] [_U]unused devices: <none>$$ sudo parted -l /dev/sdcModel: ATA WDC WD30EFRX-68E (scsi)Disk /dev/sdc: 3001GBSector size (logical/physical): 512B/4096BPartition Table: gptNumber  Start   End     Size    File system  Name     Flags 3      15.7MB  528MB   513MB                primary  raid 1      528MB   2576MB  2048MB  ext3         primary  raid 2      2576MB  4624MB  2048MB  ext3         primary  raid 4      4624MB  3001GB  2996GB  ext4         primary  raidError: /dev/md126: unrecognised disk label                                Model: Linux Software RAID Array (md)Disk /dev/md127: 2996GBSector size (logical/physical): 512B/4096BPartition Table: loopNumber  Start  End     Size    File system  Flags 1      0.00B  2996GB  2996GB  ext4$$ sudo gdisk /dev/sdcGPT fdisk (gdisk) version 0.8.8Partition table scan:  MBR: protective  BSD: not present  APM: not present  GPT: presentFound valid GPT with protective MBR; using GPT.Command (? for help): pDisk /dev/sdc: 5860533168 sectors, 2.7 TiBLogical sector size: 512 bytesDisk identifier (GUID): BDE03D26-EB85-4348-A4E0-A229FC01EE93Partition table holds up to 128 entriesFirst usable sector is 34, last usable sector is 5860533134Partitions will be aligned on 2048-sector boundariesTotal free space is 31597 sectors (15.4 MiB)Number  Start (sector)    End (sector)  Size       Code  Name   1         1032192         5031935   1.9 GiB     FD00  primary   2         5031936         9031679   1.9 GiB     FD00  primary   3           30720         1032191   489.0 MiB   FD00  primary   4         9031680      5860532223   2.7 TiB     FD00  primaryCommand (? for help): vNo problems found. 31597 free sectors (15.4 MiB) available in 2segments, the largest of which is 30686 (15.0 MiB) in size.Command (? for help): q$$ sudo mount /dev/md127 /home/xxx/wdc -t ext4mount: wrong fs type, bad option, bad superblock on /dev/md127,       missing codepage or helper program, or other error       In some cases useful info is found in syslog - try       dmesg | tail  or so
mdadm - not enough to start the array
mdadm;raid1