Cron Expression: Every Day at 2:00 AM (0 2 * * *)

The cron expression 0 2 * * * executes a task every day at 2:00 AM, making it ideal for early morning maintenance, backups, and data processing tasks during low-traffic hours.

Expression Breakdown

0 2 * * *
│ │ │ │ │
│ │ │ │ └─── Day of week: * (every day)
│ │ │ └───── Month: * (every month)
│ │ └─────── Day of month: * (every day)
│ └───────── Hour: 2 (at hour 2, 2:00 AM)
└─────────── Minute: 0 (at minute 0)

Field Values

Execution Time

This expression runs once per day at:

• 02:00 (2:00 AM)

Common Use Cases

1. Early Morning Backups

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

Create backups during early morning low-traffic hours.

2. Database Maintenance

0 2 * * * /usr/local/bin/db-maintenance.sh

Run database optimization, vacuum, or index maintenance.

3. Log Processing

0 2 * * * /usr/bin/python3 /scripts/process-logs.py

Process and analyze log files from the previous day.

4. Cache Refresh

0 2 * * * /usr/bin/python3 /scripts/refresh-cache.py

Refresh cached data, computed statistics, or pre-warm cache.

Example Implementations

Early Morning Backup Script

#!/bin/bash
# /usr/local/bin/early-backup.sh

BACKUP_DIR="/var/backups/early"
SOURCE_DIR="/var/data"
TIMESTAMP=$(date +%Y%m%d)
LOG_FILE="/var/log/backups.log"

mkdir -p $BACKUP_DIR

tar -czf "$BACKUP_DIR/backup_$TIMESTAMP.tar.gz" \
    -C $(dirname $SOURCE_DIR) \
    $(basename $SOURCE_DIR) >> $LOG_FILE 2>&1

find $BACKUP_DIR -name "*.tar.gz" -mtime +30 -delete

echo "$(date): Early morning backup completed" >> $LOG_FILE

Database Maintenance Script

#!/bin/bash
# /usr/local/bin/db-maintenance.sh

DB_NAME="app_db"
DB_USER="dbuser"
LOG_FILE="/var/log/db-maintenance.log"

# PostgreSQL maintenance
psql -U $DB_USER -d $DB_NAME -c "VACUUM ANALYZE;" >> $LOG_FILE 2>&1

# MySQL maintenance (alternative)
# mysql -u $DB_USER -p$DB_PASS $DB_NAME -e "OPTIMIZE TABLE important_table;" >> $LOG_FILE 2>&1

echo "$(date): Database maintenance completed" >> $LOG_FILE

Best Practices

1. System Load: 2 AM is typically a low-traffic period
2. Error Handling: Implement comprehensive error handling and logging
3. Locking: Use file locks to prevent concurrent execution
4. Monitoring: Set up alerts for failed jobs
5. Resource Management: Monitor CPU, memory, and I/O usage

When to Use

✅ Good for:

• Early morning backups
• Database maintenance
• Log processing
• Cache refresh
• Heavy data processing

❌ Avoid for:

• Real-time critical operations
• Tasks requiring immediate execution

Related Patterns

Conclusion

The 0 2 * * * expression is perfect for early morning maintenance tasks. It's commonly used for backups, database maintenance, and data processing during low-traffic hours when system resources are more available.