====== Running Linux on Low RAM ======

Keeping a machine with 4-8 GB of soldered RAM responsive: the goal is never hitting the disk-thrash-frozen-UI cliff.

===== earlyoom: Install This First =====

The kernel's own OOM killer waits too long. By the time it fires the desktop has been frozen for minutes. ''earlyoom'' kills the biggest process before that:

<code bash>
sudo apt install earlyoom
sudo systemctl enable --now earlyoom
journalctl -u earlyoom        # see what it has killed
</code>

Defaults are reasonable: SIGTERM under 10% memory+swap, SIGKILL at 5%. Tune in ''/etc/default/earlyoom'' (''EARLYOOM_ARGS="-m 10 -s 10"'').

===== zram: Compressed RAM Swap =====

<code bash>
sudo apt install zram-tools
zramctl
swapon --show            # should list /dev/zram0
</code>

Creates a compressed swap device in RAM (~50% of RAM by default, tunable via ''PERCENTAGE'' in ''/etc/default/zramswap''). Swap hits it before disk and it decompresses fast. Paired with ''vm.swappiness=10'', disk swap is a last resort.

===== Know the Budget =====

<code bash>
free -h                          # watch 'available', not 'free'
ps aux --sort=-%mem | head -10   # biggest users right now
</code>

On a light desktop the base system takes ~500 MB; the browser takes everything else. A handful of heavy tabs is usually the whole story.

===== Browser Discipline =====

  * Fewer tabs. Container tabs do not save RAM; closed tabs do.
  * A tab-unloader extension ("Auto Tab Discard") suspends background tabs.
  * ''about:config'' -> ''accessibility.force_disabled'' = ''true'' stops Firefox burning a few hundred MB on features nothing uses.
  * ''browser.tabs.unloadOnLowMemory'' = ''true'' (already default on Linux).
  * ''extensions.pocket.enabled'' = ''false''.

===== If It Froze Anyway =====

  1. Wait ~30 seconds. earlyoom may still be chewing.
  2. ''Ctrl+Alt+F3'' -> log in -> ''htop'' -> kill the hog (''F9'' -> SIGTERM).
  3. ''Ctrl+Alt+F1'' or F7 back to the desktop.
  4. Hard hang: hold ''Alt+PrtSc'' and slowly type ''R E I S U B'', each letter a beat apart. Safer than holding the power button.

===== Do Not Bother =====

  * "RAM cleaner" apps: Linux cache is not waste. ''available'' is what counts.
  * A bigger disk swapfile: on slow SSDs it just makes the freeze slower, not shorter. Exception: hibernation needs swap at least RAM-sized.

===== See Also =====

  * [[hosting:hardware:old_laptops|Old Laptops and Desktops]]
  * [[hosting:hardware:power_cooling|Power and Cooling]]
  * [[hosting:start|Hosting Guide]]
  * [[start|Return to wiki home]]