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Aspirant

Nov 03, 2017

Solved

Recover files using Linux

Hi All, I had a problem with the NAS and I am doing the possible to recover some of the files connecting the disks to a Linux System. I used the following commands as suggested in another discus...

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jak0lantash

Nov 17, 2017

The next steps depend on how bad you want the data back, and what risks you want to take.

Of course, you can always contact NETGEAR for Data Recovery, they offer this kind of service as a contract.

While there are some pending sectors on sdf and sdf3 is clearly out of sync (not by much), I don't understand why sdc3 doesn't get included in the RAID array, though it shows bad blocks (mdadm output).

You could try to backup the superblocks (if not already done), then recreate the RAID array. But this could result in irrevocable data loss.

(I'm not 100% sure of what is the best approach at this stage.)

Based on the outputs you provided, I think there are two possibilities.

- Again, this is dangerous territory -

Either try to recreate the RAID as "--assume-clean".

https://raid.wiki.kernel.org/index.php/RAID_Recovery#Restore_array_by_recreating_.28after_multiple_device_failure.29

http://man7.org/linux/man-pages/man8/mdadm.8.html

Or force the RAID array to assemble.

https://raid.wiki.kernel.org/index.php/RAID_Recovery#Trying_to_assemble_using_--force

For both:

Either with sde3 sdd3 sdf3
Or sde3 sdd3 sdc3

In theory, as you "--assume-clean" and only include three members, it shouldn't try to rewrite any block of data (but will overwrite the superblocks). So it shouldn't cause permanent damage. But it's a should.

Parameters from the output you provided:

/dev/sdd3:
          Magic : a92b4efc
        Version : 1.2
    Feature Map : 0x0
     Array UUID : 9c92d78d:3fa2e084:a32cf226:37d5c3c2
           Name : 0e36f164:data-0
  Creation Time : Sun Feb  1 21:32:44 2015
     Raid Level : raid5
   Raid Devices : 4
 
Avail Dev Size : 615438961 (293.46 GiB 315.10 GB)
     Array Size : 923158272 (880.39 GiB 945.31 GB)
  Used Dev Size : 615438848 (293.46 GiB 315.10 GB)
    Data Offset : 262144 sectors
   Super Offset : 8 sectors
   Unused Space : before=262064 sectors, after=113 sectors
          State : active
    Device UUID : a51d6699:b35d008c:d3e1f115:610f3d0f
 
    Update Time : Tue Oct 31 08:32:47 2017
       Checksum : 3518f348 - correct
         Events : 14159
 
         Layout : left-symmetric
     Chunk Size : 64K
 
   Device Role : Active device 1
   Array State : AAA. ('A' == active, '.' == missing, 'R' == replacing)

/dev/sdc3:
   Device Role : Active device 2
/dev/sdd3:
   Device Role : Active device 1
/dev/sde3:
   Device Role : Active device 0
/dev/sdf3:
   Device Role : Active device 3

That's what I would try:

# Backup superblocks for each partition - if not already done
for partition in /dev/sd[a-f][0-9]; do echo "Backing up superblocks for $partition"; dd if=$partition of=/root/superblocks_$(basename $partition).mdsb bs=64k count=1; done
ls -lh /root/superblocks_*

# Backup of "mdadm --examine" for each partition - new
for partition in /dev/sd[a-f][0-9]; do echo "Backing up mdadm information for $partition"; mdadm --examine $partition > mdadm_-E_$(basename $partition).txt; done
ls -lh /root/mdadm_-E_*

# Start all healthy RAID arrays - if not already done
mdadm --assemble --verbose /dev/md126 /dev/sdc4 /dev/sdd4 /dev/sde5 /dev/sdf5
mdadm --assemble --verbose /dev/md125 /dev/sde4 /dev/sdf4
mdadm --assemble --verbose /dev/md127 /dev/sde6 /dev/sdf6

# Recreate the unhealthy RAID array - new
mdadm --create --verbose --assume-clean --level=5 --raid-devices=4 --size=461579136K --chunk=64K --data-offset=131072K /dev/md124 /dev/sde3 /dev/sdd3 missing /dev/sdf3

# Check the integrity - do it again
cat /proc/mdstat
btrfs device scan
btrfs filesystem show
btrfsck --readonly /dev/md127
mount -o ro /dev/md127 /mnt
btrfs filesystem usage /mnt

Birillo71

Aspirant

Nov 13, 2017

Hi again,

Since I moved to a different server (updated compared to the previous one),

I also run again the following commands if thsi can help:

root@ubuntu:/mnt# modinfo btrfs | grep -i version

srcversion: E0B44ABE728FFF50C821A52

root@ubuntu:/mnt# btrfs device scan

Scanning for Btrfs filesystems

root@ubuntu:/mnt# btrfs fi show

warning, device 1 is missing

Label: '0e36f164:data' uuid: 96549eaf-20c0-497d-b93c-9ebd91951afc

Total devices 4 FS bytes used 3.27TiB

devid 2 size 1.85TiB used 1.61TiB path /dev/md126

devid 3 size 167.55GiB used 167.55GiB path /dev/md122

devid 4 size 763.71GiB used 705.00GiB path /dev/md123

*** Some devices missing

root@ubuntu:/mnt# modinfo btrfs

filename: /lib/modules/4.13.0-16-generic/kernel/fs/btrfs/btrfs.ko

license: GPL

alias: devname:btrfs-control

alias: char-major-10-234

alias: fs-btrfs

srcversion: E0B44ABE728FFF50C821A52

depends: raid6_pq,xor

intree: Y

name: btrfs

vermagic: 4.13.0-16-generic SMP mod_unload

signat: PKCS#7

signer:

sig_key:

sig_hashalgo: md4

root@ubuntu:/mnt# btrfs --version

btrfs-progs v4.12

root@ubuntu:/mnt# mdadm --examine --scan

ARRAY /dev/md/0 metadata=1.2 UUID=66cc8e5d:b103a0ef:bde69e91:e73c4f2b name=0e36f164:0

ARRAY /dev/md/1 metadata=1.2 UUID=5dbf97f0:611ada7b:b80708a3:4c6fee18 name=0e36f164:1

ARRAY /dev/md/data-0 metadata=1.2 UUID=9c92d78d:3fa2e084:a32cf226:37d5c3c2 name=0e36f164:data-0

ARRAY /dev/md/data-2 metadata=1.2 UUID=61df4e1a:d5eb4e15:ced7a143:0fc0057a name=0e36f164:data-2

ARRAY /dev/md/data-1 metadata=1.2 UUID=c7cd34aa:e7c54ab0:ae005385:957067e5 name=0e36f164:data-1

ARRAY /dev/md/data-3 metadata=1.2 UUID=83b7f81a:0cb02a00:b953b83f:c4092a39 name=0e36f164:data-3

Thank you

Gabriele

jak0lantash

Mentor

Nov 14, 2017

I don't understand how you got a RAID array made of sde4+sdf4, and another array made of sdc4+sdd4+sde5+sdf5. I don't see how X-RAID logic would create that.

Grouping the devices by Array UUID, these are the correct groups.

Array UUID : 9c92d78d:3fa2e084:a32cf226:37d5c3c2

/dev/sdc3:
     Array UUID : 9c92d78d:3fa2e084:a32cf226:37d5c3c2
  Creation Time : Sun Feb  1 21:32:44 2015
     Raid Level : raid5
   Raid Devices : 4
    Update Time : Tue Oct 31 08:32:47 2017
         Events : 14159
   Device Role : Active device 2
   Array State : AAA. ('A' == active, '.' == missing, 'R' == replacing)
/dev/sdd3:
     Array UUID : 9c92d78d:3fa2e084:a32cf226:37d5c3c2
  Creation Time : Sun Feb  1 21:32:44 2015
     Raid Level : raid5
   Raid Devices : 4
    Update Time : Tue Oct 31 08:32:47 2017
         Events : 14159
   Device Role : Active device 1
   Array State : AAA. ('A' == active, '.' == missing, 'R' == replacing)
/dev/sde3:
     Array UUID : 9c92d78d:3fa2e084:a32cf226:37d5c3c2
  Creation Time : Sun Feb  1 21:32:44 2015
     Raid Level : raid5
   Raid Devices : 4
    Update Time : Tue Oct 31 08:32:47 2017
         Events : 14159
   Device Role : Active device 0
   Array State : AAA. ('A' == active, '.' == missing, 'R' == replacing)
/dev/sdf3:
     Array UUID : 9c92d78d:3fa2e084:a32cf226:37d5c3c2
  Creation Time : Sun Feb  1 21:32:44 2015
     Raid Level : raid5
   Raid Devices : 4
    Update Time : Tue Oct 31 08:30:26 2017
         Events : 13612
   Device Role : Active device 3
   Array State : AAAA ('A' == active, '.' == missing, 'R' == replacing)

sdf3 is out of sync.

Array UUID : c7cd34aa:e7c54ab0:ae005385:957067e5

/dev/sdc4:
     Array UUID : c7cd34aa:e7c54ab0:ae005385:957067e5
  Creation Time : Sun Feb  1 13:35:17 2015
     Raid Level : raid5
   Raid Devices : 4
    Update Time : Fri Nov  3 18:35:57 2017
         Events : 13894
   Device Role : Active device 0
   Array State : AAAA ('A' == active, '.' == missing, 'R' == replacing)
/dev/sdd4:
     Array UUID : c7cd34aa:e7c54ab0:ae005385:957067e5
  Creation Time : Sun Feb  1 13:35:17 2015
     Raid Level : raid5
   Raid Devices : 4
    Update Time : Fri Nov  3 18:35:57 2017
         Events : 13894
   Device Role : Active device 1
   Array State : AAAA ('A' == active, '.' == missing, 'R' == replacing)
/dev/sde5:
     Array UUID : c7cd34aa:e7c54ab0:ae005385:957067e5
  Creation Time : Sun Feb  1 13:35:17 2015
     Raid Level : raid5
   Raid Devices : 4
    Update Time : Fri Nov  3 18:35:57 2017
         Events : 13894
   Device Role : Active device 2
   Array State : AAAA ('A' == active, '.' == missing, 'R' == replacing)
/dev/sdf5:
     Array UUID : c7cd34aa:e7c54ab0:ae005385:957067e5
  Creation Time : Sun Feb  1 13:35:17 2015
     Raid Level : raid5
   Raid Devices : 4
    Update Time : Fri Nov  3 18:35:57 2017
         Events : 13894
   Device Role : Active device 3
   Array State : AAAA ('A' == active, '.' == missing, 'R' == replacing)

Array UUID : 61df4e1a:d5eb4e15:ced7a143:0fc0057a

/dev/sde4:
     Array UUID : 61df4e1a:d5eb4e15:ced7a143:0fc0057a
  Creation Time : Tue Mar  3 19:40:30 2015
     Raid Level : raid1
   Raid Devices : 2
    Update Time : Tue Oct 31 11:30:21 2017
         Events : 3183
   Device Role : Active device 0
   Array State : AA ('A' == active, '.' == missing, 'R' == replacing)
/dev/sdf4:
     Array UUID : 61df4e1a:d5eb4e15:ced7a143:0fc0057a
  Creation Time : Tue Mar  3 19:40:30 2015
     Raid Level : raid1
   Raid Devices : 2
    Update Time : Tue Oct 31 11:30:21 2017
         Events : 3183
   Device Role : Active device 1
   Array State : AA ('A' == active, '.' == missing, 'R' == replacing)

Array UUID : 83b7f81a:0cb02a00:b953b83f:c4092a39

/dev/sde6:
     Array UUID : 83b7f81a:0cb02a00:b953b83f:c4092a39
  Creation Time : Thu Sep 17 18:31:39 2015
     Raid Level : raid1
   Raid Devices : 2
    Update Time : Tue Oct 31 16:22:31 2017
         Events : 1102
   Device Role : Active device 0
   Array State : AA ('A' == active, '.' == missing, 'R' == replacing)
/dev/sdf6:
     Array UUID : 83b7f81a:0cb02a00:b953b83f:c4092a39
  Creation Time : Thu Sep 17 18:31:39 2015
     Raid Level : raid1
   Raid Devices : 2
    Update Time : Tue Oct 31 16:22:31 2017
         Events : 1102
   Device Role : Active device 1
   Array State : AA ('A' == active, '.' == missing, 'R' == replacing)

If you want to double check what the 'Name' of each array is, you can re-run the command with the extra pattern:

for partition in /dev/sd[a-f][0-9]; do echo "$partition: "; mdadm --examine $partition | grep -E "Time|Events|Role|Array UUID|Array State|Raid|Name"; done

This is what I would do:
I guessed the names of the RAID arrays. I don't think it makes any difference, but you can check and amend as per the command above if you want.

# Backup superblocks for each partition
for partition in /dev/sd[a-f][0-9]; do echo "Backing up superblocks for $partition"; dd if=$partition of=/root/superblocks_$(basename $partition).mdsb bs=64k count=1; done
ls -lh /root/superblocks_*

# Start all RAID arrays
# sdf3 is out of sync
mdadm --assemble --verbose --run /dev/md127 /dev/sde3 /dev/sdd3 /dev/sdc3
mdadm --assemble --verbose /dev/md126 /dev/sdc4 /dev/sdd4 /dev/sde5 /dev/sdf5
mdadm --assemble --verbose /dev/md125 /dev/sde4 /dev/sdf4
mdadm --assemble --verbose /dev/md124 /dev/sde6 /dev/sdf6

# Check the health
cat /proc/mdstat
btrfs device scan
btrfs filesystem show
btrfsck --readonly /dev/md127
mount -o ro /dev/md127 /mnt
btrfs filesystem usage /mnt

I want to stress that I haven't tested these commands in your situation. I'm giving you honest help, to the best of my knowledge, but I'm not responsible for anything that could go wrong.

Feel free to research the topic to confirm how you want to proceed.

If you notice any error or worrying message at any step, abort and post here so I can review.

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Recover files using Linux

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