How much free space do I need to leave on SD card when running CFW?

[xHardcoreChildx]

The reason I'm asking is because I had 2 emuMMC's go bad. I have 2 Switches, 1 for each of my kids. I used a 256GB card for both Switches with 29GB set for the emuMMC partition. I installed all of the same games on each card, leaving only about 100MB free or so after all games were installed.. After shutting down, neither of them will boot back up now. I just get a black screen like it freezes up while trying to launch emuMMC. Does the system need a certain amount of free space to boot up? Isn't the 29GB partition used for system files, and does not count towards the total free space that shows on the console in system settings? I cannot find info on this anywhere and I don't want to mess up their emuMMC a 2nd time and have to start all over again. Right now, they have 1GB free still. I just want to find out how low I can go with this. I have a bunch of smaller games I'd like to add.. is 200MB free space ok? Basically I need to know if the 29GB set for emuMMC is being used by installed games, because otherwise that will tell me how much space to leave. I heard some games use up to 200MB for save files, plus I don't want to run into being locked out of the emuMMC again. Please help!

 

[Milenko]

Exfat?

 

[thesjaakspoiler]

The emuMMC is just an image of 29GB.
It will alway be 29GB and this is where games are installed if you choose to install them in the 'internal memory'.
Savefiles will also be stored inside this image.
So you can store about 28~29GB of games in the emuMMC (just like with your normal internal memory (NAND)).
You can transfer games from the internal memory (emuMMC) to the SD card through the normal Switch menu.
That can free up some space from the fixed 29GB emuMMC.
The remaining space on the SD card will be the size that the Switch sees as the SD card.
So there you should have plenty of space left. You can go the the software menu in the settings menu to check how much space you have left in either one.

The Switch doesn't know that the emuMMC is also on the same SD card.
The Switch operating system doesn't use swap files or temp files.
If you run out of space and error will show up if a game tries to save something to it's save file.
Afaik, Nintendo makes sure you don't trash your internal memory (emuMMC in this case) or SD card.
Normal save files aren't very big but there are some exceptions like Minecraft where an entire world is saved.

That black screen you mention might indeed be something else.
And probably an exFat issue as mentioned above.
I would strongly recommend using FAT32 for the SD card.
We have all been there that one day the exFat partition gets nuked.
One wrong move and the Switch trashes the entire SD card.

 

[xHardcoreChildx]

The emuMMC is just an image of 29GB.
It will alway be 29GB and this is where games are installed if you choose to install them in the 'internal memory'.
Savefiles will also be stored inside this image.
So you can store about 28~29GB of games in the emuMMC (just like with your normal internal memory (NAND)).
You can transfer games from the internal memory (emuMMC) to the SD card through the normal Switch menu.
That can free up some space from the fixed 29GB emuMMC.
The remaining space on the SD card will be the size that the Switch sees as the SD card.
So there you should have plenty of space left. You can go the the software menu in the settings menu to check how much space you have left in either one.

The Switch doesn't know that the emuMMC is also on the same SD card.
The Switch operating system doesn't use swap files or temp files.
If you run out of space and error will show up if a game tries to save something to it's save file.
Afaik, Nintendo makes sure you don't trash your internal memory (emuMMC in this case) or SD card.
Normal save files aren't very big but there are some exceptions like Minecraft where an entire world is saved.

That black screen you mention might indeed be something else.
And probably an exFat issue as mentioned above.
I would strongly recommend using FAT32 for the SD card.
We have all been there that one day the exFat partition gets nuked.
One wrong move and the Switch trashes the entire SD card.

Wow you have truly enlightened me. I feel so dumb because I've been using CFW for a couple years now and I have always thought the internal meant the actual sysNAND. It completely makes sense now. It thinks emuNAND is the internal memory when using emuMMC. Thank you! Now I have like another 27-28GB to play with. So you think 1GB is enough to leave for future save data? I was looking over some of my save files on my own Switch last night, and a lot of them are 50MB and larger.

 

[impeeza]

The emuNAND is in fact the "internal" storage when you are running emu. the Emummc partition (or files) can be reduced on size and you end with a little emunand.

have you tested your SD Cards using H2testW?

Format your cards using FATGui in FAT32 Fwith 32K cluster size

 

[Draxzelex]

Wow you have truly enlightened me. I feel so dumb because I've been using CFW for a couple years now and I have always thought the internal meant the actual sysNAND. It completely makes sense now. It thinks emuNAND is the internal memory when using emuMMC. Thank you! Now I have like another 27-28GB to play with. So you think 1GB is enough to leave for future save data? I was looking over some of my save files on my own Switch last night, and a lot of them are 50MB and larger.

Well assuming you don't fill your Switch to the brim with games, 1 GB should be enough for save data.