Serial Port

Go to drobo r/drobo • 6y ago mr_sqoogle Drobo 5N2 "Error while setting up domain configuration" (FIXED)

I figured I’d post this here for anyone else who may come across this problem and needs to get a bit more hands-on fixing their Drobo 5N2.

My Drobo 5N2 became inaccessible after updating to the latest Drobo firmware (4.2.2). After updating and rebooting, the Drobo Dashboard (ver 3.5.0 [113780]) displayed the message “Error while setting up domain configuration. Please contact support.”

I couldn’t authenticate using the Drobo Dashboard. Every time I attempted to log in, I would be immediately logged out

I couldn’t access any shares on the Drobo

None of the installed DroboApps were running

Running a port scan against the Drobo’s IP address showed only TCP ports 5000 and 5001 being open

I could ping the Drobo, so its network stack was up

Rebooting the Drobo had no effect

I had no other option other than to run “Get Diagnostics” from the “Help and Support” menu, and submit a support ticket with the log file.

Drobo responded very quickly and advised that there was a file system corruption. They supplied a firmware file to install using the Tools menu in an attempt to fix it, but the Tools menu was inaccessible as I was unable to log in to the device. Drobo suggested that I remove all the hard drives from the unit, reboot and see if I could log in and access the Tools menu from there.

Firstly, I wasn’t too keen to install additional firmware, and secondly, I wasn’t keen on removing all my drives and rebooting the unit. I didn’t want to lose any RAID information, or accidentally factory reset the Drobo and lose all my data.

So my initial aim was to see if I could get access to the unit somehow and then get all my data off first, then I could reset the Drobo 5N2, set it all up again and then copy my data back.

Doing some Googling, I found THIS post showing serial ports accessible on the DroboFS motherboard. I figured there probably wouldn’t be much difference between the design of the DroboFS and the Drobo 5N2 boards, so I set about pulling my Drobo apart.

Here is the Drobo 5N2 mainboard with similar pin headers as the DroboFS.

I figured that it's likely that the Drobo 5N2 points are for VxWorks and the Linux operating system similar to the DroboFS above, but as you can see there are slight differences between the Drobo 5N2 and the DroboFS mainboards.

The headers on the DroboFS are marked J4 and J5, and on the Drobo 5N2 they’re J2 and J3.

There are no header pins on J2 on the Drobo 5N2 mainboard

Not knowing which points are for which serial interface, VxWorks or Linux, I figured I’d solder on some pin headers and connect up some cables before putting everything back together. Once the pins were accessible from outside the Drobo I could work out what was what.

Here's a pic of the Drobo 5N2 mainboard with header pins soldered on.

I then had to mark and cut a hole in the RF shield that covers the CPU / RAM etc. I cut the hole with a Dremel Drill, and now everything fits ok.

Then it was just a matter of putting everything back together. I routed the cables under the riser board, and out the back of the Drobo 5N2. The cables fit through the Kensington Security Slot just perfectly, and are now accessible from the back of the Drobo 5N2.

I used a Bus Pirate and a multimeter to identify the pin outs. Here is the pinout and serial information.

I connected a Bus Pirate to the pins on J3 with the following connections:

Drobo 5N2 --------> Bus Pirate

GND --------> GND

Tx --------> MISO

Rx --------> MOSI

If you’re replicating this, make sure that your serial connection from your computer to the Bus Pirate with 115200.8.N.1 - use the b menu on the Bus Pirate to change it. The serial connection from the computer to the Bus Pirate needs to be the same as the serial connection from the Bus Pirate to the Drobo 5N2, otherwise you will get garbage. Configure the Bus Pirate with the following to connect to the Drobo 5N2, and you will get a root shell.

The first thing I did was reboot the Drobo 5N2 so I could see the bootup output on the console. I noticed that the Drobo was mounting /dev/sda1 to /mnt/DroboFS and issuing a warning “mounting fs with errors, running e2fsck is recommended”.

The device /dev/sda1 is where all the shares exist, plus some critical files and folders for the operation of the Drobo and its services. So it made sense that if it had issues, things were not going to work properly.

I unmounted the device, and then ran e2fsck over it, with the -y switch to automatically answer ‘yes’ to any questions that pop up.

umount /dev/sda1

e2fsck /dev/sda1 -y

The e2fsck command can take white a while to run. I noted down the files that it reported as having issues with so I could check them later. After it was completed, I rebooted the Drobo 5N2 and watched the boot-up output on the console again. This time it mounted the filesystem ok, with no warnings or errors, but I still did not have access to the Drobo. I still got the same message and connection problems.

At this point I started reading through all the bootup scripts in /etc/init.d/ to determine what was going wrong. I also noticed that the samba service was not running, so I started it to see if I could get access to the shares.

/usr/local/sbin/samba.sh start

The Drobo was now visible on the network, but it would not allow me to authenticate and access the shares. The Drobo Dashboard still displayed the same error message.

Through my investigation I also noticed that the directory /mnt/DroboFS/home was not a directory, but a file that contained a log entry from Plex. I also noticed that this directory was reported as having issues during the file system check. This directory is required by Samba to function properly (see /etc/samba/domain.inc), and It looks like the directory got stomped on at some point, so I moved the file to a different name and recreated the directory.

mv /mnt/DroboFS/home /mnt/DroboFS/home.old

mkdir /mnt/DroboFS/home

I started the nslcd service, and restarted the nasd and samba services.

/usr/local/sbin/nslcd.sh start

/usr/local/sbin/nasd.sh restart

/usr/local/sbin/samba.sh restart

The Drobo 5N2 then populated the /mnt/DroboFS/home directory with the relevant user directories, and everything started working again. I could access the shares and log in to the Drobo Dashboard where it reported everything was ok.

I restarted the Drobo and everything came up working as normal.

I hope this is helpful to someone. You probably don’t need to solder on the vxWorks pin headers, and you don’t need a Bus Pirate to connect to the Drobo 5N2. You just need a USB -> Serial adapter and three wires from the existing J3 pin header to a male DB9 connector to get access.

I'll update this post after I install some DB9 connectors in the back of my Drobo if ever I need to connect to it again in the future.

Edit: a word

The Drobo 5N does not feature a standard external serial port on its rear panel. It primarily uses an Ethernet connection for data. However, the internal motherboard contains hidden serial (UART) headers (often designated as J2 and J3) that require disassembling the chassis to access.These internal headers are typically used by advanced users or technicians for hardware debugging, accessing the Linux/VxWorks console, or recovering data from bricked units.

How to Access the Internal Serial Header:Disassembly: You will need to carefully remove the chassis casing to expose the internal motherboard.Soldering: The serial ports are raw PCB pins (unpopulated headers), meaning you will need to solder pin headers onto the J2/J3 connections.Connection: You can connect the pins to a computer using a standard USB-to-TTL serial cable.Because accessing this port requires completely voiding the warranty and entails physical teardown, most users with failed or unbootable units opt to use software-based data recovery instead.

Because accessing this port requires completely voiding the warranty and entails physical teardown, most users with failed or unbootable units opt to use software-based data recovery instead.If you are troubleshooting a failed Drobo, tell me:What LED lights are showing on the front panel?Is the device showing up in the Drobo Dashboard software?I can help you determine whether you need serial diagnostics or a software recovery solution.

The specific motherboard schematic diagram for the Drobo 5N is scarce, but the visual orientation and pinout sequence are well-documented by the hardware hacking community.

Drobo 5N Pinout & Location GuideThe Location: Orient the motherboard so the drive bays face up and the rear power/Ethernet ports face down. The serial unpopulated headers are located near the lower right edge of the board.The Ports: You will see two sets of 4-pin parallel footprints.J2 Header: The VxWorks console.J3 Header: The Linux console.

Exact Pin Sequence (Top to Bottom)Both J2 and J3 headers use a standard 3.3V TTL signal at 115200 baud (8N1). Counting from the top pin down to the bottom-most pin, the layout matches this exact sequence:VCC (3.3V - Do not connect this to your USB-to-TTL adapter, as it can fry the board)TX (Transmit - Connect to your adapter's RX pin)RX (Receive - Connect to your adapter's TX pin)GND (Ground - Connect to your adapter's Ground pin)Are you using a Bus Pirate or a standard USB-to-TTL (UART) cable to connect to these pins? Let me know if you need the exact command settings to open the terminal communication session once you hook it up!

The Exact 4-Pin SequenceBoth headers use the identical layout format. When looking at either the J2 or J3 vertical 4-pin footprint from top to bottom (moving towards the edge of the board), the sequence is:Pin NumberSignal NameConnection NotePin 1 (Top)VCC (3.3V)Do not connect to your USB-to-TTL adapter.Pin 2TXConnect to your USB adapter's RX line.Pin 3RXConnect to your USB adapter's TX line.Pin 4 (Bottom)GNDConnect to your USB adapter's GND line.Note: If you plug everything in and open your serial terminal but get gibberish text or nothing at all, swap the wires on Pin 2 and Pin 3, as some USB-to-TTL adapters label their lines by matching pin roles rather than cross-connections.Are you planning to use Putty or Screen to open the terminal connection once you hook up your USB-to-TTL adapter? I can give you the exact terminal configuration properties if you need them.