Synology cannot read its own DSM disks over USB?

[Nick]

I removed the second WD 4GB BTRFS data disk from my DS216+, put it in a HDD docking unit and connected it to the USB 3 connector on the same DS216+.
The three partitions on the disk are not recognised, with File System type: <Not Supported>.

Is this normal?

 

[Rusty]

I removed the second WD 4GB BTRFS data disk from my DS216+, put it in a HDD docking unit and connected it to the USB 3 connector on the same DS216+.
The three partitions on the disk are not recognised, with File System type: <Not Supported>.

Is this normal?

How was that drive configured while it was in the main bay? Part of an array, basic drive, SHR?

 

[Nick]

It was/is a Basic BTRFS drive. When inserted back into the second bay it is perfectly readable.

 

[Rusty]

I would say that the DSM partition on it is what's causing the problem. Can't say for sure considering I have never used the main bay Basic drive as an external device on the same NAS.

 

[Nick]

I ought to tell the whole story here. It started with a 'crashed' 2nd data HDD due to > 468 bad sectors and increasing.

Initial situation:
Bay 1: WD Red 4GB BTFRS Basic, NO RAID, system & apps
Bay 2: WD Red 4GB BTFRS Basic, NO RAID, data, crashed for bad sectors though still mounted and readable

Procedure:
Replaced crashed hdd in bay 2 with new WD Gold 10GB
Promoted healthy 4GB in bay 1 to RAID 1 together with new 10GB hdd in bay 2 (24 hrs)
Swapped WD Gold 10GB from bay 2 to bay 1, bay 2 now empty
Booted on WD Gold 10GB, obviously DSM reported a degraded RAID 1
Demoted RAID 1 to single disk (SSH mdadm --grow --raid-devices=1 --force /dev/md2)
Expanded the 4GB volume to the full 10GB (in DSM Storage Manager)

End result:
Boots fine and healthy on WD Gold 10GB in bay 1, bay 2 empty.

Now I still have the two old 4GB lying around, one healthy, one crashed but still readable.
I simply want to be able to read both through my USB dock. But they both give three partitions <Not Supported>.

Both are perfectly readable when placed back in bay 2.

So my conclusion seems to be that Synology DSM does not support reading its own (BTRFS) disks through USB? Do they? Or is something else going on?

 

[Rusty]

But they both give three partitions <Not Supported>.

Those are probably DSM partitions on there that are preventing reading the data volume as you would expect it. The drive is not mounted correctly via USB so you have problems.

 

[Robbie]

As I understand it Synology NASes will mount via USB all standard linux file systems (ext4, Btrfs etc). As soon as you (and me, as I use DSM Btrfs) deviate from the standard linux file systems you run into the 'file system not supported' wall when mounting a drive via USB.

It is an annoyance that DSM only offers 2 file systems to the user, both with limitations - Synology Btrfs provides all the DSM features but is unique to Synology, whilst ext4 has far less features in DSM (not even defrag) but offers more compatibility with external systems.

I think Telos has a better understanding of this topic so no doubt he will chime-in.

 

[WST16]

This title reminded me of an Amazon review where someone complained after buying a Lenovo Bluetooth headset that it didn’t work with his Lenovo Laptop

I know, irrelevant. I’ll see myself out

 

[Telos]

The three partitions on the disk are not recognised, with File System type: <Not Supported>.

That's odd. Synology supports btrfs (on NAS which support btrfs) and ext4... on USB. Just curious... when you connected the drive was it externally powered by the dock? Did you try both USB connections? Are you viewing this through File Station?

I don't have a btrfs disk to confirm, but FWIW, my docked PC disk shows all nine partitions including EFI and recovery.

 

[Nick]

That's odd. Synology supports btrfs (on NAS which support btrfs) and ext4... on USB. Just curious... when you connected the drive was it externally powered by the dock? Did you try both USB connections? Are you viewing this through File Station?

I don't have a btrfs disk to confirm, but FWIW, my docked PC disk shows all nine partitions including EFI and recovery.

No, I only power the dock once it's connected to the Synology, though I'm sure I also tried connecting the already powered dock+hdd, with the same result.

So far, I've only tried with the front USB 3 port. I will also try with the two rear USB 2 ports. [Edit] Same result on USB 2.

I view the "Filesystem: <Not Supported>" in Control Panel > External Devices. Nothing is mounted for me to see in File Station.

 

[Telos]

I only power the dock once it's connected to the Synology

Can your NAS "see" other drives using this dock (i.e., is the dock compatible)?

 

[Nick]

Can your NAS "see" other drives using this dock (i.e., is the dock compatible)?

Good question. I had the hardly ever used dock lying around for years. I'll try.
Also, I've thought of trying with the rear eSata port but need to dig up my eSata cable set.

I'll let you know here in the coming days.

-- post merged: 24. Mar 2021 --

Can your NAS "see" other drives using this dock (i.e., is the dock compatible)?

In fact, forget that, if dock compatibility is a possible issue. I've just decided to save us time and effort, I don't trust this Sharkoon dock anymore.
So what affordable Sata/USB3 3.5" (or even better Sata/eSata?) hdd dock can you recommend that IS compatible with my Synology DS216+? Do you happen to know of any specifically, or what specs I need to look for?

 

[Nick]

That's odd. Synology supports btrfs (on NAS which support btrfs) and ext4... on USB. Just curious... when you connected the drive was it externally powered by the dock? Did you try both USB connections? Are you viewing this through File Station?

I don't have a btrfs disk to confirm, but FWIW, my docked PC disk shows all nine partitions including EFI and recovery.

Telos, Synology support has confirmed the title of my original post: Indeed, Synology cannot read its own DSM disks over USB. This is what they wrote:

Thank you for contacting Synology support.

There will be several disk partitions when the disk is used in the internal slots. For example, two for the system and one for the data. The internal disks cannot be used in the USB port until you format the disk.

Please power off the NAS and insert the disk back to the internal slots if you still need the data in the disk.

Well, at least it's good to know this.

 

[Rusty]

Called it .

Tnx for the info, always good to have official information feedback.

 

[WST16]

So what affordable Sata/USB3 3.5" (or even better Sata/eSata?) hdd dock can you recommend that IS compatible with my Synology DS216+?

I’m using a StarTech with a DS216+II and it’s working fine so far:

https://www.amazon.com/StarTech-com-eSATA-Drive-Docking-Station/dp/B00OUSSVDG

Edit: corrected the link to the esata version

 

[jeyare]

this is standard situation, when system can't read what partition is assigned for a booting purpose. In case of Syno, they need just tune this service. Yes, they have long-long To do list for repairing of current DSM features. But they haven't a time, because they need to invest their attention to new HDDs/SSDs.
Same situation for me this week, when last Ubuntu 20.4 update has been finished. After restart and bios, just black screen was there.
So I ran Grub and it showed that it doesn't recognize partitions (4). Strange.
Back to previous version. System was ok.

 

[Telos]

I’m using a StarTech with a DS216+II

The link says 6TB. Is that a hard limit?

This is a concern I have with most docks. I suspect in part it is due to the commercially available drive size limits when the device was marketed (Synology does this with their NAS datasheets). Few docks advertise 16TB capability.

 

[WST16]

The link says 6TB. Is that a hard limit?

If it's only 6TB then it's not worth it. I've only used it with 4TB. I have a 10TB on hand but I'm very far from the dock so I can't try it. However, in the customers' answers there's an indication that 10TB worked.

 

[jeyare]

Gents,
there is just single SATA 3 specification valid for all drives, then it doesn’t matter:
- if the drive is HDD or SSD
- 125GB or 20TB capacity
- if the drive is SATA 1 or SATA 2 compatible - SATA is back compatible standard
- what interface you will use (eSATA, SATA, pSATA)

it must works. For such adapters there is just one limitation- external power source is mandatory = because you can’t get 12V supply from USB.

The link just says: tested up to 6TB
same from the vendor site