debian-boot-to-ram

In this guide we will see how to boot a Debian Live ISO completely from RAM, so that you will be able to remove the USB pendrive after booting and the live system will continue to function normally.

Note: this guide is inspired by the following video: Boot Linux Completely in RAM.

First of all, make sure you have a real live Debian ISO (not netinst). This guide was tested with debian-live-13.2.0-amd64-lxqt.iso.

Flash the ISO file onto a USB pendrive, for example using Rufus. Then boot from the pendrive.

From the boot menu, make sure the Live system option (the first one) is selected, and press e (if on a UEFI-based system) or TAB (if on a legacy BIOS system) to edit the entry. Add the toram option to the linux ... line, like this:

Then press F10 (UEFI) or ENTER (BIOS) to boot.

Warning: make sure the PC has enough RAM to store the full Debian OS image, otherwise the toram option will simply be ignored. In my case (with the aforementioned ISO file) more than 4 GB were needed, so I used a PC with 8 GB of RAM.

The boot process will take a while, as the entire OS image needs to be copied to RAM.

Tip: if you want to see the progress while the system is booting, you can press ESC during the Debian boot splash screen.

Once the system is booted, you should be able to safely unmount and unplug the USB stick.

You can verify that the system is fully running from RAM with the df -h command:

You should see that the filesystem for /run/live/medium is tmpfs, and you shouldn't see your USB pendrive mounted anywhere anymore.