OWC Mercury Elite Pro Dual RAID1 Array issue

Hardware MikroTik hardware general
1

Hello,

Just created and pair disk array in RAID1 formatted in btrfs/ext4 (not working anyways). with 3TB WD RED disks, on Hap AX3 router with 7.20 ROS. Clearly seen in linux Ubuntu, after connecting to PC. In Mikrotik router it is just shown on the list for a second, then plugged out, and that is continously to be happening, log is flooded with:

Oct/28/2025 16:54:21 disk,info add usb1 model:OWC Elite Pro Dual interface:USB 3.10 5000Mbps size:3.00T 
Oct/28/2025 16:54:21 disk,info remove usb1 
Oct/28/2025 16:54:30 disk,info add usb1 model:OWC Elite Pro Dual interface:USB 3.10 5000Mbps size:3.00T 
Oct/28/2025 16:54:30 disk,info remove usb1 
Oct/28/2025 16:54:38 disk,info add usb1 model:OWC Elite Pro Dual interface:USB 3.10 5000Mbps size:3.00T 
Oct/28/2025 16:54:38 disk,info remove usb1 
Oct/28/2025 16:54:47 disk,info add usb1 model:OWC Elite Pro Dual interface:USB 3.10 5000Mbps size:3.00T

Sometimes it even mount the partition for a very short time. Something is causing the USB to be removed.

When this happens, last part of device-path is continously increasing:

4 2-1       usb   OWC                   Elite Pro Dual         5000  bus/usb/002/024

bus/usb/002/024, 025, 026 etc.

Posted this to Mikrotik, but nobody answers from support.

Any clues?

2

Hi,

You should remeber taht:

  • AX3 is not a NAS, it's a router
  • MT uses kernel 5.6
  • btrfs/ext4 versions could have different deafault/mount settings for "full" linux than in MT kernel

Are you sure that "internal matters" of that external cage are compatibile with MT?
AFAIK the cage is intended to be compatiblie with Windows and MacOS: https://www.owc.com/solutions/mercury-elite-pro-dual-thunderbolt

3

Ok, I know it is not the NAS, but for the purposes I need, I’ve tested it with some other disk and it is satisfactory for me.

What is the MT? Some internal router linux distribution with 5.6 kernel? So called MediaTek linux?

Filesystems does not resolve the issue, no matter what is the FS, it behaves the same way. Even raw unformatted drive behaves the same.

I have also different bay based on AS2105 controller, that is connecting, but have different kind of issues (only exFat partition works some way). But let’s drop that and focus on the main array.

4

What ones? If one model works, it does not mean that another would do.

MT is commonly used on that form as short version of the name Mikrotik.

As I wrote: OWC claims Windows/MacOS compatibility. Do you see any Linux name here?

So do the "other" devices work with btrfs/ext4 with MT devices properly? Are they dual disks arrays too?

5

It doesn’t matter what OS is recommended, it matters what is the USB controller inside. It is GL3590 USB controller, which seems to be generic kernel driver, but since 5.15 version. Does these kernel revisions getting updated across RouterOS updates? Or it is static version for the device.

6

Really? IMHO the internal "magic" hides the RAID configuration and presents it as a virtual disk that could be mounted by Windows/MacOS and formatted with thaeir filesystems. Does Windows recognize btrfs or ext4 system natively in your opinion?

So, the RouterOS "see" the USB device, tries to configure it somehow but it clashes with the cage configuration going in parallel.
On the other hand: have you read the info of 5.6 kernel version. Is it a 5.15?

Back again: do you say that if I configure RAID array in brand BRAND_1 device and move disks to the device BRAND_2, then the array HAS TO work without any changes as both brands use the same USB chip?
Isn't he USB chip only the "gate" between the guts of an RAID cage and external device?

7

the internal "magic" hides the RAID configuration

The last time I used any OWC RAID of this type, it allowed both internal RAID and JBOD modes, both of which should work with Linux. Your Windows/macOS compatibility worry should not enter into it.

I recommend using it in its JBOD mode, with btrfs RAID 1 instead of md RAID. This will increase the chance of compatibility by putting the work of managing the RAID purely into the Linux kernel, without needing any user-mode tweaking as with /etc/fstab, which you haven't got direct access to in RouterOS.

It is GL3590 USB controller, which seems to be generic kernel driver, but since 5.15 version.

That's probably fatal for this project. RouterOS 7 is based on Linux kernel 5.6.3, and that isn't likely to change until RouterOS 8, the availability of which hasn't even been hinted at officially yet.

8

@tangent I’ve switched this to independent disks, however it doesn’t help, it got sligthly higher chance for one of the drives to be mounted, and then removed. I tried exfat/fat/ext4/btrfs, but seems it is not the filesystem issue, rather than usb connectivity (maybe this uncompatible driver).

Surprisingly, I have totally different linux device with 3.14 kernel rev. and the drives are recognized there as an RAID 1 array with ext4, so that is somewhat ruining the theory about the driver itself.

Well sad, that router has satisfactory (for me) transfer speeds, and could act as simple data server, but it can’t work properly, even with some simple single hdd bay. Looks like I can wait for ROS8, or buy some intel uPC to build this.

9

Or look into RDS2116.
It's made specifically for this type of application ...

Just saying.

10

Why USB? disk are recognized and served by by SATA controller. USB is only a transmission medium.

Again: Mikrotik device recognizes/allows to use only supported devices.

If I connect USB 3.0 PCI-E 1x-16x external converter and then put into it the eg. HP/DELL/Lenovo RAID controller, then MT router should be able to recognize disks connected to that controller? Or disk in the the external SAS cage?

It COULD recognize them but these devices COLD NOT work properly or it COULD NOT RECOGNIZE them at all.

Proper initialization procedures could be removed from ROS as they are not needed and it is tailored kernel.
Think of it as of embedded version of Linux.

11

Whatever, seems like for some short moment it recognizing even the partition itself:

add usb1-part1 model:OWC Elite Pro Dual size:3.00T

But then fails, without logs from kernel I guess it is a blind spot.

12

It shows info that some partition is potentaially accessible but it does not mean that it could be used.
ROS gets some info, decides: "not compatibile", disconnects the device.
Same rules apply to USB LTE modems, partially visible but not usable.

13

Ok, I’ll built it other way. Thanks for help.