Required - The following will be needed to complete the tutorial
- Computer with Linux/Unix OS
- External storage device like a Hard Drive or USB
- USB hub - A way to power the external storage device
- Raspberry Pi - Any model
Preface
While relaxing after a long day, a great work idea pops into my head… I take
out my personal computer, navigate to my cloned Documents/ folder, git pull origin master and open my file from work day.
Gasp!!…. It looks nothing like I remember. Oh shoot.. I didn’t push up todays recent changes on my work computer, and now I can’t use my notes from today to get context and help better flesh out my idea. The notes are stale. :(
A solution to this problem is to have my work computer and personal computer
access to the same exact Documents/ folder, so that any change will be
immediately be reflected on the device accessing the folder.
I could of course just set up a server/storage space in the cloud and have my
Documents/ folder deployed there. However, I had a bunch of extra Raspberry
Pi’s lying around and an external hard drive collecting dust. Might as well put
them to good use.
Raspberry Pi Set Up
First you will need to make sure that the Pi has a Linux OS installed. You can follow a fairly old tutorial of mine SD OS Image Tutorial, or use the glorious UI Imager. I highly suggest using the Imager software as it as about as simple as it gets.
Next, you will need to be able to login to the Pi from a computer. For this, we will use ssh. In order for the Pi to accept ssh connections, you might have to enable it in the Pi’s configuration. Follow along with this tutorial.
After you have enabled ssh, and rebooted the Pi, make sure to check the local
IP address of the device. Run hostname -I. The output will contain your full
address Where 192.168.0.28 is the IP number we need.
Lets guarantee this will always be the IP address by appending it to a boot file by running:
Pi
sudo echo "ip=192.168.0.28" >> /boot/cmdline.txt
Now you will have everything you to remotely login to the Pi. From your computer run the following:
Computer
ssh pi@192.168.0.28
It should prompt you for a password. The default password is raspberry, it is
advised to change it. ssh will allow us to login without having to enter a
password every time. Run the following from your computer:
Computer
ssh-copy-id pi@192.168.0.28
It will prompt you for a password, and after successfully entering, you should no longer have to enter one when logging into your Pi through ssh.
Mounting the External Hard Drive
Now we must connect and mount the External Hard Drive.
Make sure that the external hard drive is formatted as ext4. (I attempted
this with a drive formatted in vfat and I had user permission issues writing
to the drive after mounting it.)
In order to ensure that your external hard drive has enough power, and it not pulling any from the Pi, we must use the powered USB hub. Think of this as a USB splitter for your Pi, with the added benefit of providing power to any plugged in device.
With the Pi powered down sudo shutdown -h now, hook up the USB Hub to the Pi,
and plug the external hard drive into the USB Hub. Now, boot the Pi up and
after logging in from your computer run the following:
Pi
sudo blkid
The output will look something similar to:
/dev/mmcblk0p1: LABEL_FATBOOT="boot" LABEL="boot" UUID="DV4E-E470" TYPE="vfat" PARTUUID="78daa907-01"
/dev/mmcblk0p2: LABEL="rootfs" UUID="a7adb26a-8b87-4729-88c8-9f5ac069d51e" TYPE="ext4" PARTUUID="78daa607-02"
/dev/sda1: LABEL="HDD-SEAGATE" UUID="6b6eb764-8a3b-44b1-aa5f-5214c94efed4" TYPE="ext4" PARTUUID="13f31b00-01"
/dev/mmcblk0: PTUUID="77daa907" PTTYPE="dos"
The following is the external Hard Drive connected to my Pi:
/dev/sda1: LABEL="HDD-SEAGATE" UUID="6b6eb764-8a3b-44b1-aa5f-5214c94efed4" TYPE="ext4" PARTUUID="13f31b00-01"
We will be using this information to mount the external drive on startup. So make sure to copy it down somewhere.
First we need to create a mount point. I like to have mine along side
/home.But it does not really matter, you can create your mount point anywhere
on the file system. Make sure you are still logged into the Pi and run:
Pi
sudo mkdir /HDD-SEAGATE # replace /HDD-SEAGATE with your mount point
Now we must tell the Pi to mount the external drive at this mount point on startup. In order to do this you will need to edit a file as your logged in. Run the following:
Pi
sudo vi /etc/fstab
# I am used to `vim` so I will be using `vi`, but most installations
# come with `nano`. Replace `vi` with `nano` if you prefer.
Append the following line to the file and save (be careful editing this file, only ADD to the file, DO NOT change the existing content):
/etc/fstab
# Bottom of file, everything above was already in the file
/dev/sda1 /HDD-SEAGATE ext4 defaults 0 0
Where /dev/sda1 is the output path from blkid, and /HDD-SEAGATE is the path of the new mount point directory.
Now, lets make sure it will mount correctly. Run the following commands:
Pi
sudo mount -a
cd /HDD-SEAGATE # replace /HDD-SEAGATE with your mount point
echo "It works!" > permission_test
cat permission_test
You will know if you have successfully mounted the drive and have write
permissions, if you see It works! in terminal output. Now we can reboot the
Pi:
Pi
sudo reboot
Log back into the Pi and make sure the external drive is automatically mounted:
ls /HDD-SEAGATE # replace /HDD-SEAGATE with your mount point
This should output the contents of our external hard drive, including our
permission_test. Which we can now remove rm /HDD-SEAGATE/permission test
Remotley Mount the External Hard Drive
Time to mount the External Hard Drive on our computer remotely. We will need to use sshfs. After installing, create the mount point on your computer(s).
Computer
sudo mkdir /HDD-REMOTE # replace /HDD-REMOTE to with any mount point
Now for the final test. Using sshfs to remotely mount the external hard drive (which is physically mounted to the Pi)
Computer
sshfs pi@192.168.0.28:/HDD-SEAGATE /HDD-REMOTE
# Obviously replace /HDD-SEAGATE with the mount point on your Pi
# and replace /HDD-REMOTE with the mount point on your computer
You should now have the External Hard Drive mounted at your new mount point.
Computer
ls /HDD-REMOTE
Once again, this should output the contents of our external hard drive, including our permission_test. Which we can now remove rm /HDD-REMOTE/permission test
We have successfully created a new storage drive on our computers that is not physically connected. Pretty cool!
Migrate Local Folders to Remote Drive
Alrighty now its time to start moving the folders we are having syncing issues
with to the Raspberry Pi. In my case the Documents directory on my computer.
Initialize the folder as a git directory (if you haven’t already). And push up to a private
reposistory on a service like Github. (this is for back up purposes)
Clone the repo into the remote drive or move the folder.
Computer
mv ~/Documents /HDD-REMOTE/
You have successfully migrated your local folder to the remote drive. Doesn’t get much easier than that. Well, actually it does.
I don’t want to always have type the entire path /HDD-REMOTE/Documents. It should still just show up in my /home/chris directory like it did before.
Symlinks to the rescue.
Computer
ln -s /HDD-REMOTE/Documents /home/chris/Documents
There you have it! We can now edit files in our ~/Documents on any computer,
and the changes will be immedietly written on the remote server, and availble
to across all devices.
Alias the SSHFS command
No one wants to remember the entire command to mount the remote drive. Add the following to your .bashrc:
~/.bashrc
alias mount-remote='sshfs pi@192.168.0.28:/HDD-SEAGATE /HDD-REMOTE'
Now you can manually mount the drive with mount-remote (or whatever you prefer to name the alias)