[SOLVED] Problems mounting partition from a Linux-Raid array (RAID 1) using mdadm

mcpope · 06-22-2018, 12:25 PM

I have a four year old Seagate BlackArmor NAS 220 with two 2TB drives in is configured in RAID 1. Last week, the hardware (chassis) failed and the device will not boot. I have removed one of the drives and attached it to an Ubuntu image via USB.

Disk /dev/sdb: 1.8 TiB, 2000398934016 bytes, 3907029168 sectors
Units: sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes
Disklabel type: gpt
Disk identifier: D4D0B1A2-AE2B-402A-AE16-8577133024A9

Device Start End Sectors Size Type
/dev/sdb1 195312 2283203 2087892 1019.5M Linux RAID
/dev/sdb2 2283204 4373046 2089843 1020.4M Linux RAID
/dev/sdb3 4373047 5416015 1042969 509.3M Linux RAID
/dev/sdb4 5416016 3906832031 3901416016 1.8T Linux RAID

All of my data is on /dev/sdb4.

$ sudo mdadm --examine /dev/sdb4
/dev/sdb4:
Magic : a92b4efc
Version : 1.2
Feature Map : 0x0
Array UUID : b4e94ab2:ab9780a8:248eedb9:5188f365
Name : 3
Creation Time : Sun Dec 21 14:44:37 2014
Raid Level : raid1
Raid Devices : 2

Avail Dev Size : 3901415744 (1860.34 GiB 1997.52 GB)
Array Size : 1950707840 (1860.34 GiB 1997.52 GB)
Used Dev Size : 3901415680 (1860.34 GiB 1997.52 GB)
Data Offset : 272 sectors
Super Offset : 8 sectors
Unused Space : before=192 sectors, after=64 sectors
State : active
Device UUID : 407169a3:a8cb27ed:7c8e9e1d:aa715c3e

Update Time : Sun Apr 8 20:01:25 2018
Checksum : 90dd0e2b - correct
Events : 93

Device Role : Active device 0
Array State : AA ('A' == active, '.' == missing, 'R' == replacing)

I can start the RAID Array:

$ sudo mdadm -A -R /dev/md9 /dev/sdb4
mdadm: /dev/md9 has been started with 1 drive (out of 2).

But when I try to mount it, I get an error:

$ sudo mount /dev/md9 /mnt/old_hdd/
mount: unknown filesystem type 'LVM2_member'

I have no idea where to go from here. If I can get it mounted, I have another drive to export everything to, and then I can wipe and dispose of the NAS.

What should I try next to get the array mounted?

jsbjsb001 · 06-22-2018, 01:20 PM

Assuming you have "assembled" it, you may need to specify the filesystem to the mount command:

eg.

Code:

mount -t <name of filesystem here> /dev/md9 /mnt/old_hdd/

mcpope · 06-22-2018, 01:33 PM

I have tried to mount with a forced file system two different ways; ext4 and xfs (recommendations from extensive Googling)

$ sudo mount -t ext4 /dev/md9 /mnt/old_hdd
mount: wrong fs type, bad option, bad superblock on /dev/md9,
missing codepage or helper program, or other error

In some cases useful info is found in syslog - try
dmesg | tail or so.

$ sudo mount -t xfs /dev/md9 /mnt/old_hdd
mount: wrong fs type, bad option, bad superblock on /dev/md9,
missing codepage or helper program, or other error

In some cases useful info is found in syslog - try
dmesg | tail or so.

$ sudo dmesg | tail
[ 3913.366248] EXT4-fs (md9): VFS: Can't find ext4 filesystem
[ 4094.461737] XFS (md9): Invalid superblock magic number
[ 6800.486427] EXT4-fs (md9): VFS: Can't find ext4 filesystem
[ 6802.651663] EXT4-fs (md9): VFS: Can't find ext4 filesystem
[ 6824.434347] XFS (md9): Invalid superblock magic number

jsbjsb001 · 06-22-2018, 01:50 PM

Do you know which filesystem it was formatted with?

You can run the command below, which might give you an idea of which one it is:

Code:

lsblk -f

Post the output from the above command if you're not sure - but use CODE tags if you do.

mcpope · 06-22-2018, 01:52 PM

All it shows is "linux-raid-member"

Code:

$ lsblk -f
NAME    FSTYPE           LABEL UUID                                   MOUNTPOINT
sdb                                                                   
├─sdb4  linux_raid_membe 3     b4e94ab2-ab97-80a8-248e-edb95188f365   
│ └─md9 LVM2_member            usK4ce-U2Ki-pROZ-HZRS-pcqM-d1ub-enII7i 
├─sdb2  linux_raid_membe       b042c0f8-7b93-2f0b-b943-c34a201ccc7d   
├─sdb3  linux_raid_membe       8f556845-7311-d329-c732-9e3af97d7543   
└─sdb1  linux_raid_membe       d2d80e7f-682a-658c-2161-cd3196d7b9ea   
sr0                                                                   
sda                                                                   
├─sda2                                                                
├─sda5  swap                   acb1c1e3-f28a-4926-b9b4-7491d179e8cc   [SWAP]
└─sda1  ext4                   ca7decda-cc67-4680-bb3d-629aeef404dd   /

jsbjsb001 · 06-22-2018, 01:57 PM

See if the following one tells you:

Code:

sudo parted -l

mcpope · 06-22-2018, 02:00 PM

well that's annoying...

Code:

$ sudo parted -l
Model: VMware, VMware Virtual S (scsi)
Disk /dev/sda: 21.5GB
Sector size (logical/physical): 512B/512B
Partition Table: msdos
Disk Flags: 

Number  Start   End     Size    Type      File system     Flags
 1      1049kB  20.4GB  20.4GB  primary   ext4            boot
 2      20.4GB  21.5GB  1072MB  extended
 5      20.4GB  21.5GB  1072MB  logical   linux-swap(v1)


Model: ST2000DL 003-9VT166 (scsi)
Disk /dev/sdb: 2000GB
Sector size (logical/physical): 512B/512B
Partition Table: gpt
Disk Flags: 

Number  Start   End     Size    File system     Name     Flags
 1      100MB   1169MB  1069MB  ext3                     raid
 2      1169MB  2239MB  1070MB  linux-swap(v1)           raid
 3      2239MB  2773MB  534MB   ext3                     raid
 4      2773MB  2000GB  1998GB                  primary  raid


Error: /dev/md9: unrecognised disk label
Model: Linux Software RAID Array (md)                                     
Disk /dev/md9: 1998GB
Sector size (logical/physical): 512B/512B
Partition Table: unknown
Disk Flags:

jsbjsb001 · 06-22-2018, 02:02 PM

Try this to mount it:

Code:

sudo mount -t ext3 /dev/md9 /mnt/old_hdd/

mcpope · 06-22-2018, 02:04 PM

So I typed ext3, but the dmesg log says "Can't find ext4 filesystem"

Code:

~$ sudo mount -t ext3 /dev/md9 /mnt/old_hdd/
mount: wrong fs type, bad option, bad superblock on /dev/md9,
       missing codepage or helper program, or other error

       In some cases useful info is found in syslog - try
       dmesg | tail or so.

$ dmesg | tail

[ 8751.392090] EXT4-fs (md9): VFS: Can't find ext4 filesystem

jsbjsb001 · 06-22-2018, 02:13 PM

The only other things I can suggest is to:

1) Try re-assembling the RAID;

Code:

mdadm --assemble --run /dev/md9 /dev/sdb4

2) Failing that; try every filesystem listed in the man page for the mount command:

Code:

man mount

The command above will bring up the manual page for the mount command - look under "-t, --types vfstype" for a list of supported filesystems.

mcpope · 06-22-2018, 02:15 PM

Busy? Is that good or bad?

Code:

$ sudo mdadm --assemble --run /dev/md9 /dev/sdb4
mdadm: /dev/sdb4 is busy - skipping

jsbjsb001 · 06-22-2018, 02:21 PM

It looks like you may need to stop it and then try re-assembling it. Try that and then what I said above.

Code:

sudo umount /dev/md9

Failing the above or if the above gives no error;

Code:

sudo mdadm --stop /dev/md9

Then try re-assembling it as above in my last post.

mcpope · 06-22-2018, 02:26 PM

Successfully stopped and re-assembled, but it still wouldn't mount as ext3, ext4, or xfs. I will go through and try all the other filesystem types now.

Code:

$ sudo umount /dev/md9
umount: /dev/md9: not mounted
$ sudo mdadm --stop /dev/md9
mdadm: stopped /dev/md9
$ sudo mdadm --assemble --run /dev/md9 /dev/sdb4
mdadm: /dev/md9 has been started with 1 drive (out of 2).

$ sudo mount -t ext3 /dev/md9 /mnt/old_hdd/
mount: wrong fs type, bad option, bad superblock on /dev/md9,
       missing codepage or helper program, or other error

       In some cases useful info is found in syslog - try
       dmesg | tail or so.

$ sudo mount -t ext4 /dev/md9 /mnt/old_hdd/
mount: wrong fs type, bad option, bad superblock on /dev/md9,
       missing codepage or helper program, or other error

       In some cases useful info is found in syslog - try
       dmesg | tail or so.

$ sudo mount -t xfs /dev/md9 /mnt/old_hdd/
mount: wrong fs type, bad option, bad superblock on /dev/md9,
       missing codepage or helper program, or other error

       In some cases useful info is found in syslog - try
       dmesg | tail or so.

$ sudo dmesg | tail
[ 8751.392090] EXT4-fs (md9): VFS: Can't find ext4 filesystem
[ 9906.052220] md9: detected capacity change from 1997524828160 to 0
[ 9906.052228] md: md9 stopped.
[ 9912.710325] md: md9 stopped.
[ 9912.816448] md/raid1:md9: active with 1 out of 2 mirrors
[ 9912.816476] md9: detected capacity change from 0 to 1997524828160
[ 9940.310512] EXT4-fs (md9): VFS: Can't find ext4 filesystem
[ 9944.723269] EXT4-fs (md9): VFS: Can't find ext4 filesystem
[ 9950.432693] XFS (md9): Invalid superblock magic number

jsbjsb001 · 06-22-2018, 02:28 PM

What does the following command tell us now:

Code:

lsblk -f

Post it as before.

mcpope · 06-22-2018, 02:30 PM

Appears to be the same as before.

Code:

lsblk -f
NAME    FSTYPE            LABEL UUID                                   MOUNTPOINT
sdb                                                                    
├─sdb4  linux_raid_member 3     b4e94ab2-ab97-80a8-248e-edb95188f365   
│ └─md9 LVM2_member             usK4ce-U2Ki-pROZ-HZRS-pcqM-d1ub-enII7i 
├─sdb2  linux_raid_member       b042c0f8-7b93-2f0b-b943-c34a201ccc7d   
├─sdb3  linux_raid_member       8f556845-7311-d329-c732-9e3af97d7543   
└─sdb1  linux_raid_member       d2d80e7f-682a-658c-2161-cd3196d7b9ea   
sr0                                                                    
sda                                                                    
├─sda2                                                                 
├─sda5  swap                    acb1c1e3-f28a-4926-b9b4-7491d179e8cc   [SWAP]
└─sda1  ext4                    ca7decda-cc67-4680-bb3d-629aeef404dd   /