Linux Backup Lab – PHP Web App with Automated Backup

Automated, verified backup of a PHP web application and its SQLite database on Ubuntu Server, scheduled with cron and tested with a full restore.

Goal

• Host a small PHP web app that stores data in a database
• Back up both the database and the site files automatically every night
• Keep backups for 7 days (retention)
• Prove the backup works by deleting the database and restoring it
• Copy every backup to a second server (off-site) with rsync over SSH

Environment

Component	Details
Hypervisor	Hyper-V (Windows 11 host)
Web server VM	web01 – Ubuntu Server 26.04 LTS, Gen 2, 2 GB RAM, 30 GB disk, 192.168.0.138
Backup server VM	backup01 – Ubuntu Server 26.04 LTS, Gen 2, 1 GB RAM, 20 GB disk, 192.168.0.140
Network	External virtual switch, IPs from DHCP
Web server	Apache 2.4
Language	PHP 8.5
Database	SQLite 3
Access	SSH from Windows PowerShell

sudo apt update
sudo apt install apache2 php libapache2-mod-php php-sqlite3 sqlite3 -y
sudo timedatectl set-timezone Europe/Stockholm

1. The application

A simple notes app (app/index.php) where the user can write and save notes.

• Site files: /var/www/html/mysite/
• Database: /var/www/data/notes.db — stored outside the web root so it can't be downloaded through the browser
• Uses prepared statements (SQL injection protection) and htmlspecialchars (XSS protection)

sudo mkdir -p /var/www/html/mysite /var/www/data
sudo chown -R www-data:www-data /var/www/data

Verifying that the data is stored in the database:

sudo sqlite3 /var/www/data/notes.db "SELECT * FROM notes;"

2. Backup script

Script: scripts/backup-site.sh, installed at /usr/local/bin/backup-site.sh.

Step	Command	Why
Database backup	sqlite3 $DB ".backup ..."	Consistent copy even while the site is in use (a plain cp can catch the file mid-write)
Site files	tar -czf ...	Compressed archive of the PHP files
Retention	find $DEST -type f -mtime +7 -delete	Removes backups older than 7 days so the disk doesn't fill up
Logging	echo ... >> /var/log/backup-site.log	Record of every run for follow-up

File names include date and time (notes_2026-10-20_1130.db), so each backup is unique and easy to find.

sudo mkdir -p /backup
sudo chmod 700 /backup                  # only root can read the backups
sudo chmod +x /usr/local/bin/backup-site.sh
sudo /usr/local/bin/backup-site.sh      # manual test run
sudo ls -lh /backup
sudo cat /var/log/backup-site.log

3. Automation with cron

sudo crontab -e

0 2 * * * /usr/local/bin/backup-site.sh

Runs every night at 02:00 as root.

Testing the schedule: to verify cron without waiting until night, the schedule was temporarily set to every 2 minutes (*/2 * * * *). A new backup appeared every 2 minutes, after which the schedule was changed back to 0 2 * * *.

4. Restore test

A backup is only proven once it has been restored.

Simulated disaster – the database is deleted:

sudo rm /var/www/data/notes.db

The site loads but is empty. (PHP recreates an empty database because of CREATE TABLE IF NOT EXISTS, so there is no error – just no data.)

Restore from the latest backup:

sudo cp /backup/notes_2026-10-20_1158.db /var/www/data/notes.db
sudo chown www-data:www-data /var/www/data/notes.db

All notes are back.

5. Off-site copy to backup01

Backups stored on the same server as the site are lost if that server fails. A second VM, backup01, receives a copy of every backup.

web01 (192.168.0.138)                     backup01 (192.168.0.140)
/backup/  ── rsync over SSH (key) ──────▶  /backups/web01/

On backup01 – create the receiving folder:

sudo mkdir -p /backups/web01
sudo chown samir:samir /backups/web01

On web01 – SSH key for passwordless login. The backup runs as root via cron, so the key is created for root, without a passphrase:

sudo ssh-keygen -t ed25519 -C "web01-backup01"
sudo ssh-copy-id samir@192.168.0.140
sudo ssh samir@192.168.0.140 hostname     # prints "backup01" without a password

Manual rsync test:

sudo rsync -av /backup/ samir@192.168.0.140:/backups/web01/

Part	Meaning
-a	Archive mode – recursive, keeps permissions and timestamps
-v	Shows each file copied
/backup/	Source on web01 – the trailing / copies the folder's contents
samir@192.168.0.140:	Log in to backup01 as samir
/backups/web01/	Destination on backup01

rsync only transfers new or changed files, so daily runs are fast.

Added to the backup script – the off-site copy runs automatically after every backup and logs success or failure:

if rsync -a /backup/ samir@192.168.0.140:/backups/web01/; then
    echo "$(date '+%F %T') Off-site copy OK -> backup01" >> $LOG
else
    echo "$(date '+%F %T') Off-site copy FAILED -> backup01" >> $LOG
fi

Result – one run of the script creates the backup on web01 and copies it to backup01:

2026-10-23 09:20:38 Backup OK: notes_2026-10-23_0920.db, site_2026-10-23_0920.tar.gz
2026-10-23 09:20:38 Off-site copy OK -> backup01

Repository structure

linux-backup-lab/
├── README.md
├── app/index.php
├── scripts/backup-site.sh
└── screenshots/