Notes I made for people trying to use steam under Linux and keeping game files on a NTFS partition. Notes on ext4 filesystem at the end.
Also I Found this Guide - which may be better or have some details I overlook.
https://github.com/ValveSoftware/Proton/wiki/Using-a-NTFS-disk-with-Linux-and-Windows
Flatpak Warning
If your steam install is done using Flatpak that can result in the steam program being sandboxed and limited in what it can access. I have no experience with how this limits things, the flatseal tool may be needed to manage the flatpak steam program. You can setup the specific flatpak to have access to other filesystems and mountpoints outside of your home.
the command flatpak list
should show if you have steam installed via flatpak or not.
Flatpak notes at the end..
I have NO idea how the steam SNAP version differs in how it can access other locations either.
Continueing with the normal guide now..
Steam Game Directory on NTFS (fat32/exfat/vfat)
don't use the file manager to mount the filesystem
setup a /etc/fstab line to mount it at boot time
you do NOT (typically) use chown or chmod on a mounted NTFS. (you do use those commands with ext4)
example fstab entry.
UUID=1234-your-uuid-56789 /media/gamedisk ntfs-3g uid=1000,gid=1000,rw,user,exec,nofail,umask=000 0 0
You Do NOT use all of those options for ext4
On Ubuntu you can use 'ntfs' instead of ntfs-3g for the filesystem in the fstab options if you have ntfs-3g installed , it auto changes NTFS to be ntfs-3g. Other distribution may differ. When ntfs3 gets more commonplace, and stable likely people will switch to using ntfs3, and drop ntfs-3g
Newer Distribution and kernels may use the ntfs3 driver, I have not tested that driver. Try it out and see if it works.
The various issues and problems with ntfs getting mounted Read Only still apply. (hit up the numerous NTFS under Linux guides for more information) These issues also apply to exfat,vfat, fat32, and I imagine using ntfs3. Disable windows hibernate/suspend and fast boot if sharing a filesystem between linux and windows.
And ..
it's best to not use ntfs for your game storage drive , it can be slower and more of a CPU load. It does Work for me, but it is slower in my experience.
also.. there are a lot of bad/wrong/old posts/blogs/guides on this topic. so watch out for those. (some of the info here may be wrong, so dont trust this guide 100%)
This guide may be outdated or wrong when we start using ntfs3.
Also be sure to check out this guide, and the part about the compatdata directory
https://github.com/ValveSoftware/Proton/wiki/Using-a-NTFS-disk-with-Linux-and-Windows#preventing-ntfs-read-errors
bonus tip. Steam scale ui Tweak.:
set a system variable to have steam scale up it's UI.
edit your steam .desktop file to make it the default option, or make a second .desktop file for a steam 2x Launcher.
STEAM on an ext4 or other Linux filesystem.
basic outline..
format the Filesystem, get the UUID
make directory for the mount
make fstab entry.
UUID=123-YOUR-UUID /home/bob/games ext4 defaults,nofail 0 0
mount the filesystem
sudo mount /home/bob/games
make the Filesystem owned by your user.
sudo chown bob.bob /home/bob/games
reboot to make sure it mounts.
use steam and tell it to put a steam library on /home/bob/games
install games as normal.
ntfs3 notes
from user mandiblesarecute who gives an example with ntfs3
PARTLABEL=Win10 /media/win10 ntfs3 noacsrules,noatime,nofail,prealloc,sparse 0 0
noacsrules makes everything effectively 777 for when you don't need or care about fine grained access control.
This 777 mode can be annoying and a security issue in some use cases which is why it's not the default.
I had issues using Ntfs3, so for now I still use Ntfs-3g , i will test out ntfs3 again in the future as it matures.
Steam flatpak notes from another user. TimRambo1
For flatpaks you want to use the flatseal tool to allow access to the filesystem mountpoint of your steam games filesystem.
example: add mount point
/home/(username)/games/
under filesystem under the steam settings in flatseal.
The filesystem still has to be properly mounted (as shown above)
Guide Used
https://deckcentral.net/posts/allow_flatpaks_to_access_your_sd_card_with_flatseal/
STEAMDECK NOTES:
Not tried running steam games from a NTFS on my steamdeck. So I can't say how it differs from a normal Linux install.
end of my rambly guide.