Detect Empty Backup File: Verify Files Aren't Zero Bytes

Your backup script completes successfully, but the backup file is empty. Learn how to detect zero-byte backup files automatically.

Why Backup Files Can Be Empty

Backup files can be created but remain empty for several reasons:

Database connection fails but script doesn't check before writing
Disk space runs out during backup, leaving empty file
File permissions prevent writes, but script doesn't verify
Backup process is killed mid-operation
Source data is empty but backup script doesn't validate
Compression fails silently, leaving empty archive

Without checking file size, you might think backups are working when they're actually empty.

How to Detect Empty Backup Files

Check file size immediately after backup creation. Use file size checks, not just file existence. The check must be inside your backup script, not in the cron line.

Bash Example: Check File Size

#!/bin/bash
BACKUP_FILE="/backups/db-$(date +%Y%m%d).sql.gz"
pg_dump mydb | gzip > "$BACKUP_FILE"

# Get file data
FILE_EXISTS=0
FILE_SIZE=0
if [ -f "$BACKUP_FILE" ]; then
  FILE_EXISTS=1
  FILE_SIZE=$(stat -f%z "$BACKUP_FILE" 2>/dev/null || stat -c%s "$BACKUP_FILE")
fi

# Single ping with file data in payload
# In DeadManPing panel: set validation rules:
#   - "file_exists" == 1
#   - "size" > 0
# Panel will automatically detect if file is missing or empty
curl -X POST "https://deadmanping.com/api/ping/backup-daily?file_exists=$FILE_EXISTS&size=$FILE_SIZE"

Python Example: Verify File Size

import os
import subprocess
import requests

backup_file = "/backups/db-backup.sql.gz"
subprocess.run(["pg_dump", "mydb"], stdout=open(backup_file.replace('.gz', ''), "w"))
subprocess.run(["gzip", backup_file.replace('.gz', '')])

# Get file data
file_exists = os.path.exists(backup_file)
file_size = os.path.getsize(backup_file) if file_exists else 0

# Single ping with file data in payload
# In DeadManPing panel: set validation rules:
#   - "file_exists" == True
#   - "size" > 0
# Panel will automatically detect if file is missing or empty
requests.post(f"https://deadmanping.com/api/ping/backup-daily?file_exists={file_exists}&size={file_size}")

Node.js Example: Check File Statistics

const fs = require('fs');
const { execSync } = require('child_process');
const https = require('https');

const backupFile = '/backups/db-backup.sql.gz';
execSync(`pg_dump mydb | gzip > ${backupFile}`);

// Get file data
let fileExists = fs.existsSync(backupFile);
let fileSize = 0;
if (fileExists) {
  fileSize = fs.statSync(backupFile).size;
}

// Single ping with file data in payload
// In DeadManPing panel: set validation rules:
//   - "file_exists" == true
//   - "size" > 0
// Panel will automatically detect if file is missing or empty
https.request(`https://deadmanping.com/api/ping/backup-daily?file_exists=${fileExists}&size=${fileSize}`, { method: 'POST' }).end();

Monitoring Empty Backup Files

After adding file size checks to your backup script, use a dead man switch to monitor whether the check completed successfully. If your script detects an empty file and exits with error code, the ping never arrives, and you get an alert.

Include the file size in your ping payload so you can track backup sizes over time and detect gradual decreases that might indicate problems.

Bash Example: Monitor Empty Backup Files

#!/bin/bash
BACKUP_FILE="/backups/db-$(date +%Y%m%d).sql.gz"
pg_dump mydb | gzip > "$BACKUP_FILE"

# Get file data
FILE_EXISTS=0
FILE_SIZE=0
if [ -f "$BACKUP_FILE" ]; then
  FILE_EXISTS=1
  FILE_SIZE=$(stat -f%z "$BACKUP_FILE" 2>/dev/null || stat -c%s "$BACKUP_FILE")
fi

# Validate file size - exit if empty
if [ "$FILE_SIZE" -eq 0 ]; then
  echo "Error: Backup file is empty!"
  exit 1
fi

# Single ping with file data in payload
# In DeadManPing panel: set validation rules:
#   - "file_exists" == 1
#   - "size" > 0
# Panel will automatically detect if file is missing or empty
curl -X POST "https://deadmanping.com/api/ping/backup-daily?file_exists=$FILE_EXISTS&size=$FILE_SIZE"

Python Example: Monitor Empty Backup Files

import os
import subprocess
import requests
import sys

backup_file = "/backups/db-backup.sql.gz"
subprocess.run(["pg_dump", "mydb"], stdout=open(backup_file.replace('.gz', ''), "w"))
subprocess.run(["gzip", backup_file.replace('.gz', '')])

# Get file data
file_exists = os.path.exists(backup_file)
file_size = os.path.getsize(backup_file) if file_exists else 0

# Validate file size - exit if empty
if file_size == 0:
    print("Error: Backup file is empty!")
    sys.exit(1)

# Single ping with file data in payload
# In DeadManPing panel: set validation rules:
#   - "file_exists" == True
#   - "size" > 0
# Panel will automatically detect if file is missing or empty
requests.post(f"https://deadmanping.com/api/ping/backup-daily?file_exists={file_exists}&size={file_size}")

Node.js Example: Monitor Empty Backup Files

const fs = require('fs');
const { execSync } = require('child_process');
const https = require('https');

const backupFile = '/backups/db-backup.sql.gz';
execSync(`pg_dump mydb | gzip > ${backupFile}`);

// Get file data
let fileExists = fs.existsSync(backupFile);
let fileSize = 0;
if (fileExists) {
  fileSize = fs.statSync(backupFile).size;
}

// Validate file size - exit if empty
if (fileSize === 0) {
  console.error('Error: Backup file is empty!');
  process.exit(1);
}

// Single ping with file data in payload
// In DeadManPing panel: set validation rules:
//   - "file_exists" == true
//   - "size" > 0
// Panel will automatically detect if file is missing or empty
https.request(`https://deadmanping.com/api/ping/backup-daily?file_exists=${fileExists}&size=${fileSize}`, { method: 'POST' }).end();

Working Examples

See complete, working code examples in our GitHub repository:

View Examples on GitHub →

Start Detecting Empty Backup Files

DeadManPing monitors whether your backup file verification completes. Set up monitoring in 2 minutes, get alerts when backups are empty or too small. Use dead man switch to monitor empty backups automatically.

Start Monitoring Free Learn About Backup Dead Man Switch

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