I have installed the latest version of BerryBoot v2.0 onto a Raspberry Pi 3 with a 32GB SD card. I currently have Raspbian Jessie and RetroPie installed. If I go into Raspbian and set it so its file system is expanded to the SD card size what is going to happen? Will I be able to use all of the storage on the SD card, minus the storage needed for BerryBoot and RetroPie? What happens if I do the same for RetroPie?
An interesting question! Berryboot uses one partition for all systems. It is difficult to understand, so I went ahead, ran some commands and here you have how it works:
Note: I did not have retropie, but memtest. That only changes names of files in folders.
/dev/mmcblk0p1 2048 262143 260096 127M e W95 FAT16 (LBA)
/dev/mmcblk0p2 262144 15351807 15089664 7.2G 83 Linux
On second partition:
data, images, lost+found, shared, tmp (all folders)
Debian_Jessie_Raspbian_2016.05.img192 (folder), default
So berryboot mounts image AND data folder to the same place and boots from there (image is read-only). The partition is already extended.
Just for fun, I ran raspi-config (output below):
The boot partition is not mounted - cannot configure. Note that raspi-config is intended for use on only and cannot be guaranteed to work on other operating systems.
So automatic extension cannot continue, manual neither. But both OSes have access to all space (both have data folder at the same partition).