How to fix BTRFS error: unable to allocate chunk in Docker

# Show BTRFS filesystem status
sudo btrfs filesystem show /var/lib/docker

# Get detailed usage breakdown
sudo btrfs filesystem usage /var/lib/docker

# Check device statistics
sudo btrfs device stats /var/lib/docker

Overall:
    Device size:                 100.00GiB
    Device allocated:             99.00GiB
    Device unallocated:            1.00GiB

# Balance chunks with less than 5% usage (safest, minimal impact)
sudo btrfs balance start -dusage=5 /var/lib/docker

# Check balance progress
sudo btrfs balance status /var/lib/docker

# Try 10% usage threshold
sudo btrfs balance start -dusage=10 /var/lib/docker

# Then 20% if needed
sudo btrfs balance start -dusage=20 /var/lib/docker

# More aggressive - 50%
sudo btrfs balance start -dusage=50 /var/lib/docker

# Clean up completely unused chunks (requires no extra space)
sudo btrfs balance start -dusage=0 /var/lib/docker

sudo btrfs balance start -dusage=1 /var/lib/docker
sudo btrfs balance start -dusage=5 /var/lib/docker
sudo btrfs balance start -dusage=10 /var/lib/docker

# Remove stopped containers
docker container prune -f

# Remove unused images
docker image prune -a -f

# Remove unused volumes (careful - may delete data)
docker volume prune -f

# Remove build cache
docker builder prune -a -f

# Nuclear option - remove everything unused
docker system prune -a --volumes -f

# Check space reclaimed
docker system df

sudo btrfs balance start -dusage=10 /var/lib/docker

# Create a sparse file as temporary device (adjust size as needed)
sudo truncate -s 10G /tmp/btrfs-temp.img

# Add it to the BTRFS filesystem
sudo btrfs device add /tmp/btrfs-temp.img /var/lib/docker

# Now run balance (should succeed with extra space)
sudo btrfs balance start /var/lib/docker

# After balance completes, remove the temporary device
sudo btrfs device remove /tmp/btrfs-temp.img /var/lib/docker

# Clean up the temporary file
sudo rm /tmp/btrfs-temp.img

# Using a USB drive
sudo btrfs device add /dev/sdb1 /var/lib/docker
sudo btrfs balance start /var/lib/docker
sudo btrfs device remove /dev/sdb1 /var/lib/docker

# Check metadata vs data usage
sudo btrfs filesystem usage /var/lib/docker

# Balance metadata chunks (use cautiously)
sudo btrfs balance start -musage=50 /var/lib/docker

# Balance data chunks
sudo btrfs balance start -dusage=50 /var/lib/docker

# Balance both data and metadata with usage filters
sudo btrfs balance start -dusage=50 -musage=50 /var/lib/docker

# For existing directories (doesn't affect existing files)
sudo chattr +C /var/lib/docker/volumes/database_volume

# For new database containers, mount a nodatacow volume
docker run -v /nodatacow/mysql:/var/lib/mysql mysql

sudo mkdir /nodatacow
sudo chattr +C /nodatacow
# Mount volumes from here for database containers

services:
  database:
    image: postgres
    volumes:
      - /nodatacow/postgres:/var/lib/postgresql/data

# Check current storage driver
docker info | grep "Storage Driver"

# Stop Docker
sudo systemctl stop docker

# Back up Docker data (optional)
sudo cp -au /var/lib/docker /var/lib/docker.backup

# Remove Docker data directory
sudo rm -rf /var/lib/docker

# Configure overlay2 (most recommended)
sudo mkdir -p /etc/docker
echo '{"storage-driver": "overlay2"}' | sudo tee /etc/docker/daemon.json

# Start Docker
sudo systemctl start docker

# Verify new driver
docker info | grep "Storage Driver"

# Create ext4 filesystem on spare partition
sudo mkfs.ext4 /dev/sdb1

# Mount for Docker
sudo mount /dev/sdb1 /var/lib/docker

# Add to /etc/fstab for persistence
echo '/dev/sdb1 /var/lib/docker ext4 defaults 0 0' | sudo tee -a /etc/fstab

# Create maintenance script
sudo tee /usr/local/bin/docker-btrfs-maintenance.sh << 'EOF'
#!/bin/bash
# Docker BTRFS maintenance script

# Balance data chunks with low usage
btrfs balance start -dusage=10 /var/lib/docker

# Scrub filesystem for errors
btrfs scrub start /var/lib/docker

# Clean up Docker
docker system prune -f
EOF

sudo chmod +x /usr/local/bin/docker-btrfs-maintenance.sh

# Add cron job for weekly maintenance
echo "0 3 * * 0 root /usr/local/bin/docker-btrfs-maintenance.sh" | sudo tee /etc/cron.d/docker-btrfs-maintenance

# Add to monitoring system
UNALLOCATED=$(sudo btrfs filesystem usage /var/lib/docker | grep "Device unallocated" | awk '{print $3}')
echo "BTRFS unallocated space: $UNALLOCATED"