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:
cp /usr/share/initramfs-tools/scripts/local /usr/share/initramfs-tools/scripts/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-rambootreplace modified local with original file
mv /usr/share/initramfs-tools/scripts/local /usr/share/initramfs-tools/scripts/local.createramdisk
mv /usr/share/initramfs-tools/scripts/local.bak /usr/share/initramfs-tools/scripts/local
Step 6:
- update Grub.cfg to show new initramfs
ln -s /boot/vmlinuz-<version number> /boot/vmlinuz-<version number>-ramboot
update-grub
Step 7:
- reboot
- choose standart boot (no ramdisk)
- choose RAMBOOT and all your files on the root partition will be loaded to a tmpfs