Running ROMs from a Network Share

Storing your ROMs on a separate computer (NAS) solves a number of problems and has equally as many benefits.

  • It's more convenient
  • It Negates the need to transfer ROMs to your Raspberry PI MicroSD card
  • Your storage is limited only by the size of your server
  • By reducing the number of times you write to your MicroSD card you minimize the chance at corrupting it

Good to know: If you are accessing your RetroPie installation over SSH the default Raspbian username is pi and the default password is raspberry.

Copy the existing 'roms' folder structure to your server

For EmulationStation to be able to see your rom files the paths given to it within /etc/emulationstation/es_systems.cfg need to be recreated on your networked server. Connect to your RetroPie and browse to its roms folder for reference on how each system folder is named. Either copy these folders to your networked server or manually create the folders on your networked server using the same directory names.

If you prefer to not use the EmulationStation system directory names and keep the current folder structure you have on your networked server you'll need to edit es_systems.cfg. Use this command to copy the configuration file to the home directory wherein it will be editable through SMB (//RETROPIE/configs/all/emulationstation) or FTP.

cp /etc/emulationstation/es_systems.cfg /home/pi/.emulationstation/es_systems.cfg

Mount your Share

If you haven't already, now is a good time to tell Raspbian to wait for your network at boot.

sudo raspi-config

In there, select "Boot Options" and tell it Yes.

Option 1: Add to autostart.sh (Preferred if using v4.0+)

sudo nano /opt/retropie/configs/all/autostart.sh

Add the following line to the top of that file, being sure to adjust it for your personal settings, paths and options. This will make the local roms folder use your remote server roms folder instead.

sudo mount -t cifs -o username=something,password=something //REMOTEHOST/path/to/roms /home/pi/RetroPie/roms

Good to know: If you'd like to host the entire RetroPie folder remotely you can do so by removing the /roms directories from the mount command above. Make sure to have a copy of the RetroPie installation on your remote server or EmulationStation won't be able to start RetroPie!

Restart your Raspberry Pi with sudo reboot or by simply unplugging the power cord.

Alternatively, if you have a shared folder that allows guest access, you can use the following line in your autostart.sh:

sudo mount -t cifs -o guest,uid=pi //hostname/retropie /home/pi/RetroPie

This should also allow you to write save files to your NAS.

Option 2: Add to fstab

Using your favorite editor, open up fstab:

sudo nano /etc/fstab

Add the line to mount your network share. Mine looks like this:

//192.168.1.10/Storage/ROMs /home/pi/RetroPie cifs username=Username,password=Password,nounix,noserverino,defaults,users,auto 0 0

First, make sure it will mount:

sudo mount -a

Restart and check the folder to make sure it didn't have any issues mounting at boot

sudo reboot
sudo ls RetroPie/roms/snes

With any luck (and if you have a ton of SNES ROMs like myself), it will be fairly apparent that it was able to mount the share at boot.

Apple Time Capsule

This will give you read/write access, so you could keep your saves there as well (i.e. no need to create separate saves folder and editing save paths).
First create an account on your Time Capsule with the same credentials as your Pi (default: pi/raspberry).

Install cifs-utils if it's not already installed

sudo apt-get update && sudo apt-get install cifs-utils

Edit your autostart.sh file

sudo nano /opt/retropie/configs/all/autostart.sh

And instead of

sudo mount -t cifs -o username=something,password=something //hostname/retropie /home/pi/RetroPie

you enter

sudo mount -t cifs //hostname/retropie -o username=USERNAME,password=PASSWORD,sec=ntlm,file_mode=0777,dir_mode=0777 /home/pi/RetroPie

Saving Games

Go ahead and make sure everything works. Don't get to far into a game though, you might not be able to save. If you hit 'Select + R' (default save command) and it gives you an error, the easiest solution I've found is as follows.

We need to edit retroarch.cfg by deleting the # infront of the savestate_directory and savefile_directory lines and put in the desired path. I'll be using ~/RetroPie-Save. First, make the target folder:

cd
mkdir RetroPie-Save
sudo nano /opt/retropie/configs/all/retroarch.cfg

Mine looks like this:

savestate_directory = /home/pi/RetroPie-Save
savefile_directory = /home/pi/RetroPie-Save

If you already have some save files, it would be a good idea to move them to the ~/RetroPie-Save folder we created.

Scraping

At this point, everything should be good to go. You can play and save games from your childhood. If you want to make things pretty, you'll need to scrape. You may also find that scraping just doesn't work. Thank you @sselph for this tip:

A simple solution if you just want things to work would be to run

sudo /opt/retropie/supplementary/scraper/scraper -scrape_all -thumb_only -workers 4

That will parse the config the same as EmulationStation does then it will check every listed folder and scrape it placing the gamelist.xml in the rom folder for that system and the images in a folder called images in each system's rom folder. If the system isn't supported you may see a bunch of errors about not finding hashes or it might just take a while to not do anything.

The other option that is a little slower is to cd to each directory and run the scraper

cd /home/pi/RetroPie/roms/nes
sudo /opt/retropie/supplementary/scraper/scraper -thumb_only -workers 4

Troubleshooting

Games Won't Load

If you have a known working game that won't load after doing this setup, you may need to make sure the folder on your Windows system isn't marked as 'Read-Only'

Right click the folder that contains your roms and BIOS folders, select "Properties", clear the box labeled "Read Only". Sometimes this box will have a check mark or it may just be filled with gray, either way, make sure the box is clear. Select "Apply" and tell it to "Apply to all subfolders and files". After that process completes, you should be able to load your games. You may need to restart the Raspberry

Additional Help

I started a discussion on the forums for this article. I haven't written any guides for many years so this will be a good place to provide any feedback or ask any questions. If I'm not advanced enough to help, hopefully someone else can chime in or you may need to make your own thread depending on the nature of the issue. ROMs from a Network Share (Discussion)

Thank You

Thank you, everyone at the Raspberry Pi foundation, everyone involved in the development of EmulationStation and RetroPie, authors of several guides that I can't recall the names of, @sselph, @BuZz and probably a few other people.