Accessing data from old Synology JBOD

Techno Guy · 01-28-2017, 04:37 PM

So a while back I sold my dual Synology box (needed the cash), but kept the 2 drives which were setup using JBOD, planning to buy a new (more slots) Synology box one day and pop the drives in and change to a more reliable RAID x array.

Anyway, been thinking lately if there is a way to rejoin the two drives in Linux. E.g. plug them both into external USB cases and software JBOD join the two drives.

I've been googling the idea but not getting much back.

Is this possible?

TB0ne · 01-28-2017, 04:40 PM

Quote:

Originally Posted by Techno Guy

So a while back I sold my dual Synology box (needed the cash), but kept the 2 drives which were setup using JBOD, planning to buy a new (more slots) Synology box one day and pop the drives in change to a more reliable RAID x array.

Anyway, been thinking lately if there is a way to rejoin the two drives in Linux. E.g. plug them both into external USB cases and software JBOD join the two drives.

I've been googling the idea but not getting much back. Is this possible?

If you just had two drives before showing up as (let's say) /dev/sdb1 and /dev/sdc1, and you just mounted them to /mnt/one and /mnt/two...no reason you can't plug them in one at a time and read the data off, or even both via USB and read them. JBOD is just plain disks...no striping/parity/anything else.

If you're meaning "CONVERT JBOD to RAID"...I sure wouldn't, unless I had a good backup of the data. I've got a four-bay box now I use for non-critical backups, and have a software RAID on it. Using openSUSE and went through yast to do it...simple. Have it set not to mount when system boots.

Techno Guy · 01-28-2017, 04:51 PM

I'm not sure how the drives showed up before, it was a Synology NAS box and just ticked "JBOD" to join the two drives as one, and would access the one volume via the network.
I'll plug in one drive and see what I can see in Debian.

Oh, no no, I'm not planning to convert JBOD to RAID, one day I will be switching to say RAID 5 (with more drives), but I'll move the data off the old JBOD drives and just start a fresh with RAID 5 when the time comes.

TB0ne · 01-28-2017, 05:02 PM

Quote:

Originally Posted by Techno Guy

I'm not sure how the drives showed up before, it was a Synology NAS box and just ticked "JBOD" to join the two drives as one, and would access the one volume via the network.
I'll plug in one drive and see what I can see in Debian.

Oh, no no, I'm not planning to convert JBOD to RAID, one day I will be switching to say RAID 5 (with more drives), but I'll move the data off the old JBOD drives and just start a fresh with RAID 5 when the time comes.

If you joined the two drives as one, they weren't JBOD anymore. The NAS unit may have done a RAID Mirror on them (unknown, depends on model and what options you selected), but the easiest way to test is to plug one in via USB adapter, and see what you can see. If you can mount it, you're in luck.

Otherwise...going to be VERY difficult.

Techno Guy · 01-28-2017, 05:14 PM

Hmm, doesn't look good

I do have screenshots somewhere of what settings I all had.

Code:

root@debian:~#  fdisk -l

Disk /dev/sda: 20 GiB, 21474836480 bytes, 41943040 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: dos
Disk identifier: 0x72be9bb6

Device     Boot    Start      End  Sectors  Size Id Type
/dev/sda1  *        2048 40136703 40134656 19.1G 83 Linux
/dev/sda2       40138750 41940991  1802242  880M  5 Extended
/dev/sda5       40138752 41940991  1802240  880M 82 Linux swap / Solaris

Disk /dev/sdb: 3.7 TiB, 4000787025920 bytes, 976754645 sectors
Units: sectors of 1 * 4096 = 4096 bytes
Sector size (logical/physical): 4096 bytes / 4096 bytes
I/O size (minimum/optimal): 4096 bytes / 4096 bytes
Disklabel type: dos
Disk identifier: 0x00000000

Device     Boot Start        End    Sectors Size Id Type
/dev/sdb1           1 4294967295 4294967295  16T ee GPT

root@debian:~# mount -o ro /dev/sdb1 ./4tb/
mount: special device /dev/sdb1 does not exist

syg00 · 01-28-2017, 06:40 PM

That looks like mis-interpreted data - were the drives partitioned by the NAS box, or used as raw devices ?. What does "file -s /dev/sdb" return.

Techno Guy · 01-28-2017, 06:52 PM

They were 2 new 4TB drives which yes the NAS box (Synology DS214+) formatted to JBOD using what looks like ext4 volume format

I just found a photo which says it was JBOD and ext4, still sure I have more, with more details. (those filesystem errors were due to a power cut, and were fixed and the NAS box was running fine before I took the drives out.)
https://cl.ly/1P1W1y0K3b2x

Code:

root@debian:~# file -s /dev/sdb
/dev/sdb: DOS/MBR boot sector; partition 1 : ID=0xee, start-CHS (0x0,0,1), end-CHS (0x3ff,254,63), startsector 1, 4294967295 sectors, extended partition table (last)

syg00 · 01-28-2017, 07:32 PM

Quote:

Originally Posted by TB0ne

Otherwise...going to be VERY difficult.

Basically says it all I reckon.
Without knowing how the (presumably) proprietary RAID0 is constructed, can't offer any help.

Techno Guy · 01-28-2017, 09:46 PM

Edit:
So it would seem the Seagate external case I was plugging my NAS drive into does something to the data so that the computer doesn't read it as a RAID drive

The Seagate case: (0xEE)
https://cl.ly/080H2g2c2L2z

The connectland case:
https://cl.ly/0i2B2i1K0y2c

So I'll buy another connectland case and then assemble the linear (RAID?) and I should be golden.

Thanks for your help guys.

Code:

root@debian:~# mdadm --examine /dev/sdc
/dev/sdc:
   MBR Magic : aa55
Partition[0] :   4294967295 sectors at            1 (type ee)

root@debian:~# mdadm --examine /dev/sdc1
mdadm: No md superblock detected on /dev/sdc1.

root@debian:~# mdadm --examine /dev/sdc2
mdadm: No md superblock detected on /dev/sdc2.

root@debian:~# mdadm --examine /dev/sdc3
/dev/sdc3:
          Magic : a92b4efc
        Version : 1.2
    Feature Map : 0x0
     Array UUID : 408d7a50:b220bfb8:b136c02d:3e6a374e
           Name : homenas:2
  Creation Time : Fri Jan 17 19:19:16 2014
     Raid Level : linear
   Raid Devices : 2

 Avail Dev Size : 7804592833 (3721.52 GiB 3995.95 GB)
  Used Dev Size : 0
    Data Offset : 2048 sectors
   Super Offset : 8 sectors
   Unused Space : before=1968 sectors, after=0 sectors
          State : clean
    Device UUID : 3524dfbe:85122c51:25fe2ff4:c7de1591

    Update Time : Fri Jan 17 19:19:16 2014
       Checksum : d43ac9f5 - correct
         Events : 4

       Rounding : 64K

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

TB0ne · 01-29-2017, 09:04 AM

Quote:

Originally Posted by Techno Guy

Edit:
So it would seem the Seagate external case I was plugging my NAS drive into does something to the data so that the computer doesn't read it as a RAID drive

The Seagate case: (0xEE) https://cl.ly/080H2g2c2L2z
The connectland case: https://cl.ly/0i2B2i1K0y2c

So I'll buy another connectland case and then assemble the linear (RAID?) and I should be golden. Thanks for your help guys.

Code:

root@debian:~# mdadm --examine /dev/sdc
/dev/sdc:
   MBR Magic : aa55
Partition[0] :   4294967295 sectors at            1 (type ee)

root@debian:~# mdadm --examine /dev/sdc1
mdadm: No md superblock detected on /dev/sdc1.

root@debian:~# mdadm --examine /dev/sdc2
mdadm: No md superblock detected on /dev/sdc2.

root@debian:~# mdadm --examine /dev/sdc3
/dev/sdc3:
          Magic : a92b4efc
        Version : 1.2
    Feature Map : 0x0
     Array UUID : 408d7a50:b220bfb8:b136c02d:3e6a374e
           Name : homenas:2
  Creation Time : Fri Jan 17 19:19:16 2014
     Raid Level : linear
   Raid Devices : 2

 Avail Dev Size : 7804592833 (3721.52 GiB 3995.95 GB)
  Used Dev Size : 0
    Data Offset : 2048 sectors
   Super Offset : 8 sectors
   Unused Space : before=1968 sectors, after=0 sectors
          State : clean
    Device UUID : 3524dfbe:85122c51:25fe2ff4:c7de1591

    Update Time : Fri Jan 17 19:19:16 2014
       Checksum : d43ac9f5 - correct
         Events : 4

       Rounding : 64K

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

Good luck..you're going to need it. Unless your RAID controller hardware matches, you're going to have a REALLY bad time trying to do what you're after, with no data loss. If this was RAID1 (mirrored), you should be able to put ONE of the disks into the USB enclosure and mount/read/copy data off. After that, nothing you do will be harmed.

Techno Guy · 01-31-2017, 03:31 PM

So today my other 3.5" HDD enclosure arrived, I plugged in the other 4TB drive and it showed up correctly now, connected both to my Debian VM and ran the assemble command, mounted it and bingo, done!

I must've been lucky that Synology uses just the standard Linear RAID (which they call JBOD) which mdadm can rejoin no problem.
I can access all 8TB files no problem. Though information about doing this seems very limited on the internet, so I hope this will help others trying to do the same.

Code:

root@debian:~# mdadm --assemble --scan 
mdadm: /dev/md/homenas:2 has been started with 2 drives.

root@debian:~# mkdir /root/8tb/
root@debian:~# mount /dev/md/homenas\:2 /root/8tb/