Running roms off a USB

iconrumble

@Dominus The video opts to ediit the file es_systems.cfg, to point emulationstation to the usb. The problem with that is that this cfg file can be overwritten when updating retropie.
I prefer to create a symbolic link ( https://en.wikipedia.org/wiki/Symbolic_link ) pointing to the usb. Retropie will still look for the rom on the sd card but will be redirected by this link to the usb.
To do this, create a "psx" folder on your usb, ssh into the pi, go to home/retropie/roms, delete the existing "psx" folder and enter sudo ln -s /media/usb0/psx psx This will create a link in your sdcard roms folder, named "psx", pointing to "psx" folder in your usb. First follow the video to find the correct path to your usb (usb0, usb1, etc).

Dominus

I have yet to try this, but I am sure it will work so thank you in advance! But I had another question... are you able to split the roms for one system up onto 2 different USB Sticks?

iconrumble

@Dominus instead of symlink the entire "psx" folder, you can keep the "psx" folder on the sd and create two symlinks inside that, each one for each usb.
Example:
go to home/retropie/roms/psx;
enter sudo ln -s /media/usb0/psx USB0 --> this creates the symlink for the fist usb
enter sudo ln -s /media/usb1/psx USB1 --> this creates the symlink for the second usb
don't forget to confirm the usb paths.

Dominus

@iconrumble Thanks man! That is so much easier then what is explained in the wiki. I haven't tried the 2 usb Symbolic Link to same folder, but at least I know it is possible. Thanks!

Juakin

@iconrumble said in Running roms off a USB:

you can use the usb the two ways. I personally have console roms on my sd card and have an usb stick for psx isos
My usb gets automounted on boot; I then added a symbolic link in the retropie roms folder linking the folder on the usb with the psx isos, using ln -s [target] [linkname].

Dude, this is exactly the way I want to configure my RetroPie, can you please explain (or give a link) on how to automount USB's on Retropie??
Also, if you place a PSX iso in /home/pi/RetroPie/roms/psx and at the same time have more of them in /media/usb0/roms/psx will load all of them, or you can only see the ones on the USB??

Dominus

@iconrumble I never did no automounting, do I have to do that?!? It seems to have worked already?

Juakin

@iconrumble nevermind I've already done it...
@Dominus I had to, my usb's didn't mount automatically when I connected them, In fact if I was on the desktop (lxde) and connect one of them it asked for a password, so yes, I had to edit the "fstab" file and add automount to my devices.

iconrumble

@Juakin In my case, I swapped the psx folder on the sd card with a symlink, so I can only see isos on the usb. You could create the symlink inside the sd psx folder (just like a subfolder), that way you can put isos in the sd card and the usb.

@Dominus @Juakin My 64gb fat32 usb get's automounted at boot, I didn't have to edit the fstab or do anything else. I'm running of retropie 3.8 image updated to 4.0.1

Juakin

@iconrumble said in Running roms off a USB:

@Juakin In my case, I swapped the psx folder on the sd card with a symlink, so I can only see isos on the usb. You could create the symlink inside the sd psx folder (just like a subfolder), that way you can put isos in the sd card and the usb.

That's exactly what I did, now I can load my ISOS from both places.
Thanks for the info.

AndersHP

Wow, having just read this topic I'm getting convinced that even I can do this.

Does this generally slow down or in other ways stress the Retropie? And what are the exact benefits of running ROMs off a USB, if there's Space enough on the SD?

Apart from that, do you just use USB Sticks, or USB external harddives? Are there any min. requirements for the USB (read/write speed etc)?

What about Steven Selph's scraper. will this also understand the symlink and still scrape the games?

dankcushions

@AndersHP said in Running roms off a USB:

Wow, having just read this topic I'm getting convinced that even I can do this.

Does this generally slow down or in other ways stress the Retropie?

no. USB transfer will probably be faster than SD cards (?), but in any case it doesn't really matter.

And what are the exact benefits of running ROMs off a USB, if there's Space enough on the SD?

the benefits are listed here: https://github.com/RetroPie/RetroPie-Setup/wiki/Running-ROMs-from-a-USB-drive

Apart from that, do you just use USB Sticks, or USB external harddives?

i use a USB stick. a harddrive seems excessive. that amount of ROMs would surely grind ES to a hault.

Are there any min. requirements for the USB (read/write speed etc)?

no.

What about Steven Selph's scraper. will this also understand the symlink and still scrape the games?

i don't use symlinks, i use the recommended mount method. i would have thought it would, though.

spannernick1

Edited... question already be asked.

Dominus

@AndersHP @dankcushions
I find that save states take a hell of a long time to save! I have PSX and GBA on my USB stick, and I bet it takes 10 seconds or more to save PSX games (loading is pretty instant it seems), and GBA about 5 seconds? Just looking into why that is (could be my USB stick?) or to move the save states to the SD card.

dankcushions

@Dominus said in Running roms off a USB:

@AndersHP @dankcushions
I find that save states take a hell of a long time to save! I have PSX and GBA on my USB stick, and I bet it takes 10 seconds or more to save PSX games (loading is pretty instant it seems), and GBA about 5 seconds? Just looking into why that is (could be my USB stick?) or to move the save states to the SD card.

it may just be the emulation. the original psx memory cards were slow, so the games / bios may have no idea they are being run on much better hardware. it's the same reason load times still exist for psx games, despite running on machines that could hold the whole ISO in memory.

Dominus

@dankcushions I don't know, maybe. But I'm talking about the RetroArch save states not just the regular memory card save points, as those actually work faster lol... plus I have similar issues, though not as long, with the GBA on USB.

Dominus

I just timed it and it took around 23 seconds to save state on PSX, and with GBA it took around 2.5 seconds. I tried 2 different USB sticks so it's not the USB. I don't have mine mounted, would that make a difference?

AndersHP

Reading the guide on Github, it seems that you have to move the entire RetroPie folder onto the USB.

Does this mean that the SD card in general is not really used anymore? I thought that it was only for running games off the USB drive. But what is exactly getting moved onto the USB? Just to get a better understanding...

Also, the guide says both "copy" and "moving" the above mentioned, but the command states 'mv'... Will some files be present on both SD card and USB drive?

dankcushions

@AndersHP said in Running roms off a USB:

Reading the guide on Github, it seems that you have to move the entire RetroPie folder onto the USB.

Does this mean that the SD card in general is not really used anymore? I thought that it was only for running games off the USB drive. But what is exactly getting moved onto the USB? Just to get a better understanding...

The retropie folder only contains the roms and bios files. The operating system, setup-script, configs, emulators, etc, are still on the SD.

Also, the guide says both "copy" and "moving" the above mentioned, but the command states 'mv'... Will some files be present on both SD card and USB drive?

yeah that's a mistake - good spot! it moves the folder, not copy. there's no point having it on the SD if it's on the USB.

AndersHP

So, I just realized that since december, the Github guide has changed, with an auto mount option now available.

I'm about to try this now #fingerscrossed
What I don't understand is, still, the ROMS and Retropie folder seems to get copied, not moved..?

And if the USB ROM transfer service is set to ON (as the guide tells), and I start copying games to my new ROMs dedicated USB, won't the system start copying everything onto the SD card?

AndersHP

OK, to answer my own questions, if the USB drive is inserted into the Pi, it's read before the RetroPie folder that still exist on the SD card (even figures like normal in the File Manager), and if the USB drive is not inserted, the system looks at the SD card instead.

So what I'm doing now, is after the automount method has copied everything onto the USB, I unplug the USB drive and remove all my ROMs from the File Manager (as this will make the File Manager look at the content of the SD). After that, I can be sure that there's no ROMS on the SD, and everything is running off the USB.