A script to facilitate transfer of files from my NAS to an HDD

rsync-auto-restart.sh

#!/bin/bash

RSYNC_BIN="/usr/local/opt/rsync/bin/rsync"


#  sudo nohup ./rsync_auto_restart.sh > rsync_output.log 2>&1 &
SOURCE="/Volumes/photo/2025/"
DEST="/Volumes/2024/2025/"
# SOURCE="/data/source/"
# DEST="/data/dest/"
SPEED_THRESHOLD_MB=30    # Minimum acceptable speed in MB/min
INTERVAL_SEC=60          # Interval to check speed (in seconds)

RSYNC_LOG="/Users/justinwagg/Projects/photo-transport/rsync_speed_check_2025.log"
EVENT_LOG="/Users/justinwagg/Projects/photo-transport/rsync_restart_log_2025.txt"  

# RSYNC_LOG="/logs/rsync_speed_check.log"
# EVENT_LOG="/logs/rsync_restart_log.txt"

rm -f "$RSYNC_LOG"

if [[ "$OSTYPE" == "darwin"* ]]; then
  RSYNC_LAUNCH="$RSYNC_BIN"
else
  RSYNC_LAUNCH="setsid rsync"
fi

# Helper to log timestamped messages
log_event() {
    echo "$(date '+%Y-%m-%d %H:%M:%S') $1" >> "$EVENT_LOG"
}

# This function runs rsync and logs it
run_rsync() {
    log_event "Starting rsync process..."
    $RSYNC_LAUNCH -avh \
        --exclude='@eaDir/' \
        --exclude='@SynoResource/' \
        --exclude='@SynoRecycle/' \
        --exclude='.AppleDouble/' \
        --exclude='.DS_Store' \
        --exclude='Thumbs.db' \
        --exclude='._*' \
        --exclude='.Spotlight-V100/' \
        --exclude='.Trashes/' \
        "$SOURCE" "$DEST" \
        --log-file="$RSYNC_LOG" &
        RSYNC_PID=$!

    RSYNC_PID=$!
    echo "$RSYNC_PID" > /tmp/rsync_pid
    log_event "Started rsync with PID $RSYNC_PID"
}

get_dir_size_bytes() {
    dir="$1"

    if [[ "$OSTYPE" == "darwin"* ]]; then
        # macOS: use du -sk and convert KB to bytes
        du -sk "$dir" | awk '{print $1 * 1024}'
    else
        # Linux/Synology: use du -sb for exact byte count
        du -sb "$dir" | awk '{print $1}'
    fi
}

wait_for_disk_idle() {
    device="$1"
    low_write_threshold_kbps=1024
    low_await_threshold_ms=50
    required_idle_checks=2
    idle_checks=0

    log_event "Waiting for disk $device to become idle..."

    while true; do
        if [[ "$OSTYPE" == "darwin"* ]]; then
            # macOS: no await data, only write KB/s
            stats=$(iostat -d 1 2 | awk -v dev="$device" '$1 == dev' | tail -1)
            write_kbps=$(echo "$stats" | awk '{print int($3)}')  # macOS shows r/s, w/s, rKB/s, wKB/s
            w_await=0  # Not available on macOS
        else
            # Linux/Synology
            stats=$(iostat -dkx 1 2 | awk -v dev="$device" '$1 == dev' | tail -1)
            write_kbps=$(echo "$stats" | awk '{print int($9)}')   # write KB/s
            w_await=$(echo "$stats" | awk '{print int($13)}')     # await time in ms
        fi

        log_event "$device write speed: ${write_kbps} KB/s, w_await: ${w_await} ms"

        if (( write_kbps < low_write_threshold_kbps && w_await < low_await_threshold_ms )); then
            idle_checks=$((idle_checks + 1))
            log_event "Idle check $idle_checks / $required_idle_checks"
        else
            idle_checks=0
            log_event "Still busy. Resetting idle check counter."
        fi

        if (( idle_checks >= required_idle_checks )); then
            log_event "Disk $device is idle."
            break
        fi

        sleep 5
    done
}



# This function checks the speed and restarts rsync if necessary
check_speed() {
    bytes_before=$(get_dir_size_bytes "$DEST")
    sleep "$INTERVAL_SEC"
    bytes_after=$(get_dir_size_bytes "$DEST")
    bytes_diff=$((bytes_after - bytes_before))
    mbps=$((bytes_diff / INTERVAL_SEC / 1024 / 1024))

    log_event "Transfer speed: ${mbps} MB/s (Δ: $((bytes_diff / 1024 / 1024)) MB over $INTERVAL_SEC sec)"

    if (( mbps < SPEED_THRESHOLD_MB )); then
        log_event "Transfer speed dropped below ${SPEED_THRESHOLD_MB} MB/s. Restarting rsync."
		if kill -0 $RSYNC_PID 2>/dev/null; then
		    log_event "Killing rsync process group for PID $RSYNC_PID"
		    kill -- -$RSYNC_PID 2>/dev/null         # graceful group kill
		    sleep 2
		    kill -9 -- -$RSYNC_PID 2>/dev/null      # forceful group kill if still alive
		else
		    log_event "rsync PID $RSYNC_PID not found — already exited?"
		fi
		sleep 5
		pkill -f "[r]sync -avh"
		if ps -p $RSYNC_PID > /dev/null; then
		  log_event "rsync still running after kill!"
		else
		  log_event "rsync successfully terminated"
		fi		
        wait_for_disk_idle sdq    # Replace 'sdf' with your actual device find w df -h  grep usb
        sleep 5
        run_rsync
    fi
}



# Start rsync
run_rsync

# Wait a few minutes before the first speed check
FIRST_WAIT_SEC=600  # 10 minutes

log_event "Waiting $FIRST_WAIT_SEC seconds to allow rsync to initialize..."
sleep "$FIRST_WAIT_SEC"

# Monitor and restart if needed
while true; do
    if ! kill -0 $RSYNC_PID 2>/dev/null; then
        log_event "rsync process exited unexpectedly. Restarting..."
        run_rsync
        log_event "Waiting $FIRST_WAIT_SEC seconds after restart..."
        sleep "$FIRST_WAIT_SEC"
    else
        check_speed
    fi
done