How to move rootfs to external usb storage

Move RootFS to External USB Storage (Bookworm)

This guide explains how to move the root filesystem (rootfs) of a Raspberry Pi running Bookworm to an external USB storage device.

1. Prepare Your External USB Storage

sudo fdisk /dev/sdX
# Create a new partition (type Linux) and format it
sudo mkfs.ext4 /dev/sdX1

Replace /dev/sdX with the actual device name of your USB storage.

2. Mount the USB Storage

sudo mkdir /mnt/usb
sudo mount /dev/sdX1 /mnt/usb

3. Copy RootFS to USB

sudo rsync -aAXv / --exclude={"/dev/*","/proc/*","/sys/*","/tmp/*","/run/*","/mnt/*","/media/*","/lost+found"} /mnt/usb

4. Modify Boot Configuration

sudo nano /boot/cmdline.txt

Change the root= parameter to point to your USB device, e.g., root=/dev/sdX1.

5. Reboot the Raspberry Pi

sudo sync
sudo reboot

Your Raspberry Pi should now boot from the external USB storage. 🚀