Recovering Data Off a Synology NAS HDD

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sonyxperiageek

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#282799 12-Mar-2021 18:51

Hi folks,

DSM suddenly said my Synology NAS' partition has crashed. Upon opening Storage Manager, and doing all the SMART tests, they all come back as healthy, but only has 13 bad sectors.

Does anybody know how I can recover my data from this drive outside of the Synology NAS? I bought a SATA to USB adapter and my Windows PC can see it in Disk Management, but I can't see it in File Explorer because it's not NTFS/FAT format.

I can't remember exactly, but I think i set it up initially as RAID 0.

Thanks.

Sony

Tinkerisk

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#2672407 12-Mar-2021 18:55

Raid0 can't be restored. FileSys is either ext4 or btrfs. No backup? Too bad.

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Mehrts

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#2672410 12-Mar-2021 19:05

A PC running some flavour of Linux would be the best option to recover the data. Fire up a "live" version of Linux Mint for an easy-to use one These deal with EXT4 by default.

Buuuut, if it was RAID 0, then you'll only have some of your data on that drive & that might be a challenge to restore too.

RAID 0 on its own is a very very dangerous thing to do if you care about the data stored using that method. There is nothing redundant about it, but can improve drive performance. It breaks down your files into separate blocks across the drives for faster read/writes.

RAID 1 is a simple mirror, and this is usually the best option for basic redundancy. If one drive fails, you've still got all your data intact.

Raid 0 and 1 (typically called RAID 10) can be combined for better performance and redundancy, but at the cost of needing to purchase more drives.

sonyxperiageek

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#2672413 12-Mar-2021 19:12

Thanks guys, I only had the one drive in the NAS. Does that change things with RAID 0?

Sony

Mehrts

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#2672416 12-Mar-2021 19:20

You can only have RAID with multiple drives. (Redundant Array of Independent Drives) aka more than one.

Since it's single disk, then obviously everything will be on that one.

Make a bootable USB stick with Linux Mint on it, and pop that into a PC. It'll allow you to run it without actually installing anything onto that PC.
Connect the drive using the USB-SATA cable & it should appear as an external drive (similar to Windows).

Now you should be able to copy the files over to a new drive. Hopefully nothing has been corrupted by the original drive, but you won't know until you get it onto a new one to verify it.

Going back to RAID, this is why it's beneficial to have at least a dual-drive NAS, as one drive can be mirrored with the second one. One drive can fail, and you can swap that out with a new one, usually without having to power-down the NAS. It'll have the data from the good drive copied over to it, and you carry on business as usual.

Tinkerisk

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#2672417 12-Mar-2021 19:21

When only one drive, you have no Raid0, just a single drive. You CAN try to rescue some data of it like posted before.

edit: another post was faster :-)

sonyxperiageek

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#2672421 12-Mar-2021 19:27

Ah yeah thought so. Thanks. I've got a Raspberry Pi running Ubuntu so I'll plug it into a USB port there and see what comes up.

Yeah, I just bought two new 4 TB drives to replace in my Synology NAS, and set it up as RAID 1.

I still don't understand why the Synology NAS suddenly said that the Partition had crashed, but the disk was healthy.

Sony

sonyxperiageek

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#2673528 13-Mar-2021 00:21

Hmm doesn't seem to show up as a disk in Ubuntu's File Explorer. Only see the current SD card.

This is what fdisk says (it's the 2.7TB drive):

Sony

Dynamic

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#2673631 13-Mar-2021 09:25

Another option... https://www.howtogeek.com/112888/3-ways-to-access-your-linux-partitions-from-windows/

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K8Toledo

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#2673649 13-Mar-2021 10:31

sonyxperiageek:

Ah yeah thought so. Thanks. I've got a Raspberry Pi running Ubuntu so I'll plug it into a USB port there and see what comes up.

Yeah, I just bought two new 4 TB drives to replace in my Synology NAS, and set it up as RAID 1.

I still don't understand why the Synology NAS suddenly said that the Partition had crashed, but the disk was healthy.

Can you post a screenshot of SMART stats?

Spyware

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#2673650 13-Mar-2021 10:40

sonyxperiageek: Hmm doesn't seem to show up as a disk in Ubuntu's File Explorer. Only see the current SD card.

This is what fdisk says (it's the 2.7TB drive):

https://raid.wiki.kernel.org/index.php/A_guide_to_mdadm

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MackinNZ

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#2673651 13-Mar-2021 10:42

I've used ext2explore (now called ext2read) before for recovering data from QNAP drives and it worked very well.

jamesrt

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#2673677 13-Mar-2021 11:18

In a nutshell, the Synology is using the Linux LVM (Logical Volume Manager) to manage the disk space - even with just a single drive, it'll have an LVM layout, so that later it could be mirrored etc much more easily.

If you google Linux LVM, you may find some commands that will help - but basically, you'll need to activate the Volume Group and the Logical Volumes before you can mount them.

This may also help you:

# mount
...
/dev/mapper/vg1000-lv on /volume1 type ext4 (rw,relatime,user_xattr,synoacl,barrier=0,journal_checksum,data=writeback,jqfmt=vfsv0,usrjquota=aquota.user,grpjquota=aquota.group)

root@DiskStation:~# lvdisplay
--- Logical volume ---
LV Path /dev/vg1000/lv
LV Name lv
VG Name vg1000
LV UUID fAGrn1-Thkx-KSqK-dDAl-1sDd-P1gi-P2G4y0
LV Write Access read/write
LV Creation host, time ,
LV Status available
# open 1
LV Size 1.81 TiB
Current LE 475776
Segments 1
Allocation inherit
Read ahead sectors auto
- currently set to 4096
Block device 253:0

root@DiskStation:~# vgdisplay
--- Volume group ---
VG Name vg1000
System ID
Format lvm2
Metadata Areas 1
Metadata Sequence No 2
VG Access read/write
VG Status resizable
MAX LV 0
Cur LV 1
Open LV 1
Max PV 0
Cur PV 1
Act PV 1
VG Size 1.81 TiB
PE Size 4.00 MiB
Total PE 475776
Alloc PE / Size 475776 / 1.81 TiB
Free PE / Size 0 / 0
VG UUID 8ntcTn-Q195-gr65-bnxh-6PqN-FVLK-99WN0q

From my Synology DJ212J, which is running a RAID-1 mirror across 2 2TB drives, FYI.

The actual logical volume is an EXT4 filesystem (shown with the mount command), and the other output is the LVM structure in use on my Synology.

Also: https://wiki.debian.org/LVM and https://davelevy.info/wiki/raspberry-pi-and-lvm/ may give you some help.

sonyxperiageek

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#2673808 13-Mar-2021 16:40

Thanks guys, I started ddrescue on my Windows laptop last night (supposedly finishes tomorrow), so will see what happens when I mount the finished image from ddrescue.

Sony

K8Toledo

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#2673880 13-Mar-2021 17:38

sonyxperiageek: Thanks guys, I started ddrescue on my Windows laptop last night (supposedly finishes tomorrow), so will see what happens when I mount the finished image from ddrescue.

If no luck with ddrescue you might try TestDisk. It can rebuild partition tables.

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openmedia

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#2674083 14-Mar-2021 08:37

Try

- mdadm --examine /dev/sda1

- mdadm --examine /dev/sda2

- mdadm --examine /dev/sda5

With luck they are just standard Linux raid devices you can restart with MDADM.

Generally known online as OpenMedia, now working for Red Hat APAC as a Technology Evangelist and Portfolio Architect. Still playing with MythTV and digital media on the side.