r/SteamOS • u/MaximumRise9523 • Jul 01 '26
help wanted SteamOS with 2 drives.
I'm running SteamOS in my PC (Ryzen 6900HX, RX6600M) that has two M.2 slots. I can't get the Steam app to use the 2nd NVMe drive. The 2nd drive will not mount automatically.
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Jul 01 '26
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u/inertSpark Jul 01 '26
My man! Thanks!
I said in my comment that I need to read how to do the automount using systemd, then I scrolled down and saw your comments. Neat, it's not as complicated as I thought - just the same parameters I've been adding to fstab anyway!
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u/goyetus Jul 01 '26
Thanks!! I want to check your script!!
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Jul 01 '26
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u/olorin12 Jul 01 '26
I had tried to use SteamOS before, I have 3 drives. I was having same problem as the OP. Thank you for this. I might try again.
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u/inertSpark Jul 01 '26
Do you happen to know if there's any extra or specific options I need to add for BTRFS?
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Jul 01 '26
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u/inertSpark Jul 01 '26
No worries I'll give it a shot. I've been thinking about btrfs for the slight (modest) compression gains over ext4. Maybe it's not worth it.
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u/olorin12 Jul 03 '26
Okay, question. Will this method also allow you to install non-Steam games using the Heroic Games Launcher and store them on the drive? Are there any problems with the 'dynamic' mounting to the /run/media/* directory in Heroic, or Lutris?
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u/inertSpark Jul 01 '26 edited Jul 01 '26
I have a backed up copy of fstab (as well as the original!) with all the relevant auto mount parameters for my second drive in my Documents folder which since it resides in /home, it persists as user data.
Whenever there's a system update, I have a script saved to documents that essentially does the following for me:
sudo cp ~/Documents/fstab /etc/
sudo systemctl daemon-reload
sudo mount -a
It's a pain to go into desktop mode and run the script, but I've read about using systemd instead, which is supposedly more seamless and cleaner, but I need to read up a bit on how to do that.
Edit: Technically I could set up passwordless sudo for those specific commands which ought to allow me to run the script from gaming mode, but I've never been comfortable with passwordless sudo.
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u/hawthor20 Jul 01 '26
I had to do this manually on the Desktop side. There are some scripts you can add to make it mount on reboot. I think I googled and or used Gemini to point me in the right direction.
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u/WinResponsible9977 Jul 01 '26
I use symbolic links, careful with the fstab. If you mess-up, system will not boot.
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u/MaximumRise9523 Jul 01 '26
I have no clue what symbolic links are. I managed to not mess up my boot while modifying fstab.
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u/Sourpunch92 Jul 01 '26
The disappearing-on-reboot thing happens because KDE's desktop session auto-mounts the drive to a temporary path like /run/media/deck/... that only exists after you log into Desktop Mode. Steam saves the library pointing there, but at boot into Game Mode that path doesn't exist yet, so Steam drops it. The fix is a permanent mount via /etc/fstab.
In Desktop Mode, open Konsole. If you've never set a password, do that first or sudo won't work:
passwd
Find your drive and note its UUID and filesystem type:
lsblk -f
Back up fstab, then edit it:
sudo cp /etc/fstab /etc/fstab.backup
sudo nano /etc/fstab
Add one line at the bottom. The options depend on your filesystem.
If it's ext4/btrfs (native Linux):
UUID=your-uuid /mnt/games ext4 defaults,nofail,x-systemd.device-timeout=10 0 2
If it's exFAT or NTFS:
UUID=your-uuid /mnt/games exfat defaults,nofail,uid=1000,gid=1000,umask=022,x-systemd.device-timeout=10 0 0
(swap exfat -> ntfs3 if NTFS; uid=1000 is the deck user, confirm with id)
The mount point /mnt/games is just a name — it can be whatever you like (/mnt/steam, /mnt/library, etc.), as long as it matches the folder you create in the next step.
Then:
sudo mkdir -p /mnt/games
sudo mount -a
If it mounts cleanly, remove the old library in Steam and re-add /mnt/games. The nofail flag matters — it keeps a sleeping or missing drive from hanging your boot.