Protect your Raspberry Pi µSD card (use read-only filesystem)

WARNING!! EXPERIMENTAL SETTINGS: create a backup copy of your µSD card before applying these settings!

• makes filesystem read only to prevent filesystem corruption after power fail
• writes to µSD card are redirected to overlay filesystem in RAM

Prerequisites:

• Raspbian Stretch with Desktop (2017-09-07)
• Raspbian Stretch Lite (2017-09-07)

scripts based on: https://gist.github.com/mutability/6cc944bde1cf4f61908e316befd42bc4

Make Filesystem Read-Only

Disable SWAP

sudo dphys-swapfile swapoff
sudo systemctl disable dphys-swapfile
sudo apt-get purge dphys-swapfile

Disable man indexing

sudo chmod -x /etc/cron.daily/man-db
sudo chmod -x /etc/cron.weekly/man-db

Move /var/log to tmpfs

Append to file /etc/fstab

tmpfs /var/log tmpfs size=70M 0 0

sudo nano /etc/fstab

Disable unwanted log files

sudo nano /etc/rsyslog.conf

Install script

cd /tmp
wget https://raw.githubusercontent.com/janztec/empc-arpi-linux-readonly/master/install-experimental.sh -O install-experimental.sh
pi@raspberrypi:/tmp $ sudo bash install-experimental.sh

Check Status

• Read only mode is enabled

pi@raspberrypi:/home/pi $ sudo df
Filesystem     1K-blocks    Used Available Use% Mounted on
...
/dev/mmcblk0p2  15205520 4309620  10215392  30% /ro
overlay-rw        262144  115108    147036  44% /rw
...

Make Filesystem Read-Write Again

• sudo nano /boot/cmdline.txt
• change overlay=yes to overlay=no
• Ctrl+o and Ctrl+x
• sudo reboot

Check Status

• Read only mode is disabled

pi@raspberrypi:/home/pi $ sudo df
Filesystem     1K-blocks    Used Available Use% Mounted on
/dev/mmcblk0p2  15205520 4309756  10215256  30% /