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Raspberry Pi 4 NAS

October 2019


NAS stands for Network Attached Storage, which is essentially a miniature home server that allows you to access your external files (for example, a large photo library or media center) over your home wifi network. Depending on how you configure it, you can even access your files over the internet so that your don't have to take up valuable storage space on your laptop or phone. For my use, I mainly wanted to store my old Logic/Ableton projects, It also serves as remote backup that's always connected, so it is easier to make frequent backups compared to a typical external hard drive.

Some advantages of using a Raspberry Pi as a NAS are the price, size and... The cheapest model starts at just $35, and can even function as a full-fledged desktop computer if you decide later on to upgrade your NAS. The Pi's ARM-based processor architecture is also very power-efficient, so even though the server will be on all of the time, it won't raise your electric bill significantly. Although it is possible to complete this project using previous versions of the Raspberry Pi, the addition of gigabit ethernet, USB 3, and a faster processor make the Raspberry Pi 4 a much more suitable NAS server.

There are of course some disadvantages to such a setup. First, the Pi's processor is not powerful enough to support transcoding on Plex, so we're limited to direct play over our LAN, and streaming our media over the internet isn't possible. Also we're limited to gigabit ethernet since there's no way to add 10 gigabit to the Pi. This connection can support a single drive at nearly full read/write speed, but anything faster like a RAID setup or SSD will easily saturate a gigabit ethernet connection. But for just a backup server or for local Plex hosting, the Pi works perfectly. Having considered these limitations, let's get started.

The supplies I used for this project are

Setting up the Pi

For this project, we are going to be using Open Media Vault (OMV), an open-source operating system designed for NAS devices. Go here to download OMV. Make sure you get the correct version, which for us is the one whose filenname ends in a "4" (for Raspberry Pi 4).

Extract the zip, and burn the image to your SD card. For this, I used SD Card Formatter to erase the card, and Balena Etcher to burn the image to the SD card.

SSH into the Pi

Plug in the SD card to the Pi and power it on. At this point, it's easiest if you plug-in HDMI cable to an external monitor, and you will see your PI's IP address on the screen. Alternatively, you can place a file called "ssh" (no file extention) on to the boot directory of your SD card and find your ip using

arp -a

on another computer on your LAN. Run the command once while your Pi is off, and again after you power it on. The new IP in the list is your Pi's IP. On another computer, type

ssh root@[your Pi's IP]

and log on with the password "openmediavault". We will use this SSH window to enter terminal commands to our Pi.

Setting up OMV

Login screen to OMV

Next, open a web browser on another computer and go to your Pi's IP. The default username is "admin" and enter "openmediavault" for the password, so enter these credentials to log in. Now you should see the default overview screen. The first thing we are going to do is change the administrator password. In the main sidebar, go to General Settings -> Web Administrator Password, enter a new password of your choosing, and click save.

Disks screen of OMV

Now it's time to set up our storage devices. Make sure that your external hard drives are plugged into the Raspberry Pi, and go to the Disks menu in the OMV sidebar. All of the disks should be visible here under the labels /dev/sda, /dev/sdb, etc. We have to erase each disk before setting them up in OMV. (IMPORTANT: all data will be lost after the next step. Make sure you have a backup of any data currently on the disk that you can restore after erasing). Once you are sure there's no data to be lost, select each disk and click Wipe.

File systems screen of OMV

Next go to the File Systems tab, and click Create. Select one of your drives from the devices drop-down, choose a name for the drive, and leave the file system as EXT4. Click OK, and OMV will begin formatting the drive. Once it is finished, you may have to click Mount to mount the drive.

Users screen of OMV

We also have to add some users to our server. Go to the User side menu, and click Add. It's easier later on if the first user you add is the administrator (you). Enter a name and password, and optionally an email or comment. Click Save. Any time you change a setting in OMV, you will be prompted to apply the setting, so click "Apply". You can also assign users to groups in the Group menu, but we will skip this step since we won't have very many users for this NAS.

Shares screen of OMV

We can now set up our shared folders. These are what will show up as the network "drives" when each of your users connect to your NAS. You can choose permissions for each of your shares, allowing just one, or as many users access it as you would like. Click Add, and make a name for your new shard folder. The default path and permissions can be left as-is. Choose a device to store your shared folder. The only consideration here is that shares can not be split across devices, so be sure to plan well for how large you anticipate the folder to be. Click Save.

Privileges screen of OMV

Now select your new shared folder and click Privileges. Choose what users you want to be able to access the folder, and click Save.

SMB screen of OMV

We will be using the SMB protocol for our shares. It has excellent cross-platform compatibility, so it will work with any Windows, Mac, or Linux device (This does not work for Apple Time Machine backups. For this setup, see below). Go to the SMB/CIFS sidebar menu, click Enable, and Save. Then go to the Shares tab in the top menu. We need to add our shared folders here. Click add and select your shares in from the drop down. The default parameters here are all fine, but you could enable the recycle bin if you would like the option of recovering deleted files on you shares. Click Save and Apply.

That's it! We now have a SMB shared folder on our home network. In order to connect to it, follow these instructions, and enter your raspberry pi's IP address as the SMB name.

Setting up an Apple Time Machine backup

Getting time machine to work on OMV follows many of the same steps as SMB. Create a new share, assign permissions for the correct user, but now instead of adding it to SMB, we need to go to the Apple Filing sidebar menu. Click Enable and Save. The go to Shares, and add your new Time Machine share. The only setting you have to change is "Enable Time Machine support for this share." Now you should be able to see that share as a backup option on the Time Machine setting on your Mac. Just log in using your OMV account, and the Time Machine will start backing up your files.

Setting up Docker and Plex

Note: for this section, it's easiest if you already have a shared "config". There's no need to add it as a SMB share.

Since OMV is a server operating system, we use containers to run applications more efficiently than with virtual machines. Docker is a platform for running applications inside of containers, and we will use Docker to run our Plex server. Go to the Plugins sidebar menu, and search for Docker. Click Install. If you don't see Docker, you may have to install OMV-Extras. At this point, you may also have to restart OMV by clicking the three dots in the top right, and clicking Reboot. You should now see that Docker has its own entry in the sidebar menu, under Services.

In the Docker menu, go to the search box under Docker Images, and search for "lsioarmhf/plex". We use the ARM distribution because we're using a Raspberry Pi. If we built our NAS using typical PC or server hardware, we would use "linuxserver/plex". Click start to install the image.

Docker screen of OMV

Next, select Plex under Docker Images, and click Run Image. In the screen that pops up, add a Container Name. Set the Restart Policy to "Always". Make the Network Mode "Host". Under Environment Variables, we need to add a row called "PUID", and set the value to 1000. Add another row called "PGID", with the value of 100. Note: these values are only accurate if the first user you added to OMV was the admin. Use

id -u username

in the Raspberry Pi terminal to find the UID of a specific user and

id -g username

to find the GID.

Scroll down to Volumes and Bind Mounts. This is where we tell Docker how to map the directories that Plex will be looking for. Under Container Path, add "/media", and make the Host path wherever you plan to keep your Plex media on one of your shared folders. Next add a new container path named "/config" and point it to the host path "/sharedfolders/config/Plex". If you don't have a Plex directory, Docker will create one for you. Lastly add the "/transcode" path as "/sharedfolders/config/transcode". Click Save to start the container.

To access Plex, go to "[your ip]:32400/web". Follow these directions for setting up Plex. Since we already mapped our directories inside of Docker, when prompted for our media locations, we can just add the Plex default "/movies", "/tv", "/music", and "/photos" directories.

And we're done! We can add our media to the Plex directories and start enjoying our content wirelessly, from any device on our LAN.

Improve SMB read speed on MacOS

In recent versions of MacOS, the existence of a .DS_Store file on a network share can significantly slow down the time it takes to read directory names and contents. This terminal command disables MacOS from reading the .DS_Store file. See here for more info.

defaults write DSDontWriteNetworkStores -bool TRUE

A note on RAID

Originally, I was hoping to use this setup with RAID 0 (disk striping) or RAID 5 (striping with parity) in order to increase read times from the NAS. While OMV is capable of these configurations, gigabit ethernet is actually the main bottleneck, and even a single drive is able to saturate this connection. Setting up drives in RAID actually lowered read speeds for me due to the increased overhead of software RAID.

Similarly, I also do not recommend using RAID 1 (disk mirroring). Since this is a personal NAS (as opposed to a small business, for example), we are not as concerned about coherency of our shares in the event of a drive failure. Since RAID is not designed as to be a backup, you are much better off setting up an Rsync task to backup your data. This way, you eliminate an additional single point of failure (software RAID on the Pi). If a drive fails, you can just install a new drive, copy your data from the backup, and resume using the NAS as normal.