How to Set Up Automated MySQL Backups with Shell Script and Cron on Linux

ByAkensai

Learning how to set up automated MySQL backups with shell script and cron on Linux is one of the smartest things you can do for your server. Database failures happen without warning. A single corrupted table or accidental DROP can wipe out months of data. Manual backups are easy to forget. Automating the process removes human error from the equation entirely. In this tutorial, you’ll create a shell script that dumps your MySQL databases, compresses the output, and runs automatically on a schedule using cron. By the end, you’ll have a reliable backup system running silently in the background every single day.

Prerequisites for Setting Up Automated MySQL Backups with Shell Script and Cron on Linux

Before you start, make sure you have the following in place.

What you need:

– A Linux server running Ubuntu 20.04, 22.04, or Debian 11/12
– Root or sudo access to the server
– MySQL or MariaDB installed and running
– Basic familiarity with the terminal and text editors like nano or vim
– Estimated time to complete: 20–30 minutes

You should also have mysqldump available on your system. It ships with most MySQL and MariaDB installations by default. Confirm it’s installed by running:

mysqldump --version

If the command returns a version number, you’re good to go. You’ll also want a dedicated directory to store your backups. Keep them outside your web root for security. A path like /var/backups/mysql works well. Create it now if it doesn’t exist:

sudo mkdir -p /var/backups/mysql
sudo chmod 750 /var/backups/mysql

For reference on MySQL backup best practices, check the official MySQL Backup and Recovery documentation.

How to Set Up Automated MySQL Backups with Shell Script and Cron on Linux: Step-by-Step

This event shares similarities with: How to Set Up Automated MySQL Backups with Cron on Linux

Follow these steps carefully. Each one builds on the last.

Step 1: Create a MySQL backup user

Don’t use your root MySQL account in scripts. Create a dedicated backup user with limited permissions instead.

Log into MySQL:

sudo mysql -u root -p

Then run these SQL commands:

CREATE USER 'backupuser'@'localhost' IDENTIFIED BY 'StrongPassword123!';
GRANT SELECT, SHOW DATABASES, LOCK TABLES, RELOAD, REPLICATION CLIENT ON . TO 'backupuser'@'localhost';
FLUSH PRIVILEGES;
EXIT;

Replace StrongPassword123! with a strong password of your choice.

Step 2: Store credentials securely

Never hardcode passwords directly in your script. Use a MySQL options file instead.

Create the file:

sudo nano /etc/mysql/backup.cnf

Add this 

[client]
user=backupuser
password=StrongPassword123!

Lock down permissions so only root can read it:

sudo chmod 600 /etc/mysql/backup.cnf
sudo chown root:root /etc/mysql/backup.cnf

Step 3: Write the backup shell script

Create the script file:

sudo nano /usr/local/bin/mysql_backup.sh

Paste in this script:

#!/bin/bash

# Configuration
BACKUP_DIR="/var/backups/mysql"
DATE=$(date +"%Y-%m-%d_%H-%M-%S")
RETENTION_DAYS=7
OPTIONS_FILE="/etc/mysql/backup.cnf"
LOG_FILE="/var/log/mysql_backup.log"

# Get list of databases
DATABASES=$(mysql --defaults-extra-file="$OPTIONS_FILE" -e "SHOW DATABASES;" | grep -Ev "(Database|information_schema|performance_schema|sys)")

# Loop through each database and dump it
for DB in $DATABASES; do
    FILENAME="$BACKUP_DIR/${DB}_${DATE}.sql.gz"
    mysqldump --defaults-extra-file="$OPTIONS_FILE" 
        --single-transaction 
        --routines 
        --triggers 
        "$DB" | gzip > "$FILENAME"

    if [ $? -eq 0 ]; then
        echo "[$DATE] SUCCESS: Backed up $DB to $FILENAME" >> "$LOG_FILE"
    else
        echo "[$DATE] ERROR: Failed to back up $DB" >> "$LOG_FILE"
    fi
done

# Delete backups older than retention period
find "$BACKUP_DIR" -name ".sql.gz" -mtime +$RETENTION_DAYS -delete
echo "[$DATE] Cleanup: Removed backups older than $RETENTION_DAYS days" >> "$LOG_FILE"

This script backs up every user database, compresses each file with gzip, logs the result, and automatically deletes backups older than 7 days.

Step 4: Make the script executable

sudo chmod 750 /usr/local/bin/mysql_backup.sh
sudo chown root:root /usr/local/bin/mysql_backup.sh

Step 5: Test the script manually

Run it once to confirm everything works:

sudo /usr/local/bin/mysql_backup.sh

Check the backup directory:

ls -lh /var/backups/mysql/

You should see compressed .sql.gz files for each database. Also check the log:

cat /var/log/mysql_backup.log

Step 6: Schedule the script with cron

Open the root crontab:

sudo crontab -e

Add this line to run the backup every day at 2:00 AM:

0 2    /usr/local/bin/mysql_backup.sh

Save and exit. Cron will now trigger your backup automatically every night. You can adjust the schedule to fit your needs. For example, 0 /6 runs every 6 hours.

To learn more about cron syntax, the Ubuntu CronHowto guide is a great reference.

Troubleshooting Common Errors When Automating MySQL Backups on Linux

Even a well-written script can hit snags. Here are the most common issues and how to fix them.

Error: Access denied for user ‘backupuser’

This means the MySQL user doesn’t have the right privileges. Log back into MySQL as root and re-run the GRANT statement from Step 1. Make sure you ran FLUSH PRIVILEGES afterward.

Error: mysqldump: Got error: 2002

This usually means MySQL isn’t running. Check its status:

sudo systemctl status mysql

Start it if it’s stopped:

sudo systemctl start mysql

Backup files are empty or zero bytes

Check your options file path in the script. Also confirm the backup user has SELECT and LOCK TABLES privileges on the target database.

Cron isn’t running the script

Cron runs in a minimal environment. Always use full paths in your script. Check cron’s log to see if it’s even triggering:

grep CRON /var/log/syslog | tail -20

Disk space filling up

Reduce RETENTION_DAYS in the script or move backups to remote storage like an S3 bucket or SFTP server. Monitoring disk usage with df -h regularly is a good habit.

Tip: Always verify your backups by restoring one to a test database. A backup you can’t restore is useless.

Conclusion

You now have a fully working automated backup system for your MySQL databases. The script runs silently every night, compresses your data, logs results, and cleans up old files automatically. This kind of setup protects you from accidental data loss, hardware failure, or human error. Knowing how to set up automated MySQL backups with shell script and cron on Linux is a core skill for any Linux administrator. From here, you might want to extend this setup by sending backup files to a remote server, adding email alerts on failure, or encrypting your backup files before storage. Each of those additions builds on exactly what you’ve done here today.

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