How to boot from RAM on debian

boot-from-ram-debian.md

Booting Debian from a RAM disk

This guide is adapted from http://reboot.pro/topic/14547-linux-load-your-root-partition-to-ram-and-boot-it/

What you need:

• lots of RAM
• Debian based distribution or any that supports booting from initramfs
• mkinitramfs or a tool to build a new initramfs
• some linux knowledge
• no need to create an image
• no need for Grub4Dos
• no need for a "special driver"

Step 1: Choose a distribution thats supports booting from initramfs. (like ubuntu)

Step 2: Install to harddisk. Make sure you split it into multiple partitions (/, /boot, /home, swap, ...).

Step 3: Boot your new system, install updates, drivers if neccessary (this will improve performance), strip it down to the minimum. Every file will be loaded to RAM ! A fresh install uses about 2 GB auf harddisk-space.

Step 4: modify /etc/fstab :

cp /etc/fstab /etc/fstab.bak find the line specifing the root partition and change it in: none / tmpfs defaults 0 0* save

Step 5: edit the local script in your initramfs: cd /usr/share/initramfs-tools/scripts/* make a backup of /usr/share/initramfs-tools/scripts/local cp local local.bak* modify local, find this line:

# FIXME This has no error checking

# Mount root

mount ${roflag} -t ${FSTYPE} ${ROOTFLAGS} ${ROOT} ${rootmnt}

change it to:

# FIXME This has no error checking

# Mount root

#mount ${roflag} -t ${FSTYPE} ${ROOTFLAGS} ${ROOT} ${rootmnt}

mkdir /ramboottmp

mount ${roflag} -t ${FSTYPE} ${ROOTFLAGS} ${ROOT} /ramboottmp

mount -t tmpfs -o size=100% none ${rootmnt}

cd ${rootmnt}

cp -rfa /ramboottmp/* ${rootmnt}

umount /ramboottmp

• save
• execute, or rebuild initramfs mkinitramfs -o /boot/initrd.img-ramboot* replace modified local with original file cp -f local.bak localStep 6:
• modify this file (needs a better solution) /boot/grub/grub.cfg* copy the first boot entry and replace the /initrd line with this: /initrd /boot/initrd.img-ramboot* label the new entry as RAMBOOT This will boot our generated initramfs instead the original one. Step 7:
• reboot
• choose standart boot (no ramdisk)
• choose RAMBOOT and all your files on the root partition will be loaded to a tmpfs

Can anyone confirm this is still valid in Debian 12 ?