Backup and Restore

Data loss can destroy a business. Regular backups are non-negotiable for any production MongoDB deployment. This episode covers every backup and restore method available in MongoDB, from simple dump-and-restore to automated scheduled backups.

Backup Tools Overview

• mongodump — Creates BSON backup files (fast, compact, preserves types)
• mongorestore — Restores from mongodump output
• mongoexport — Exports to JSON or CSV (human-readable, for single collections)
• mongoimport — Imports from JSON or CSV files

mongodump — Full Database Backup

# Backup ALL databases
mongodump --out /backup/full-backup-$(date +%Y%m%d)

# Backup a specific database
mongodump --db blogApp --out /backup/blogApp-$(date +%Y%m%d)

# Backup a specific collection
mongodump --db blogApp --collection posts --out /backup/posts-$(date +%Y%m%d)

# Backup with authentication
mongodump --host localhost --port 27017 \
    --username admin --password secret \
    --authenticationDatabase admin \
    --db blogApp --out /backup/

# Backup a remote database
mongodump --uri "mongodb+srv://user:pass@cluster.mongodb.net/mydb" \
    --out /backup/remote-backup

# Compressed backup (much smaller file size)
mongodump --db blogApp --gzip --out /backup/compressed

# Backup with a query filter (only published posts)
mongodump --db blogApp --collection posts \
    --query '{"published": true}' \
    --out /backup/published-posts

mongorestore — Restore from Backup

# Restore all databases from a backup directory
mongorestore /backup/full-backup-20240115

# Restore a specific database
mongorestore --db blogApp /backup/blogApp-20240115/blogApp

# Restore a specific collection
mongorestore --db blogApp --collection posts \
    /backup/blogApp-20240115/blogApp/posts.bson

# Restore with --drop (drops existing data before restoring)
mongorestore --drop /backup/full-backup-20240115

# Restore compressed backup
mongorestore --gzip /backup/compressed

# Restore to a different database name
mongorestore --db blogApp_staging \
    /backup/blogApp-20240115/blogApp

# Restore with authentication
mongorestore --host localhost --port 27017 \
    --username admin --password secret \
    --authenticationDatabase admin \
    /backup/full-backup-20240115

mongoexport — Export to JSON/CSV

# Export a collection to JSON
mongoexport --db blogApp --collection users \
    --out /exports/users.json

# Export to CSV
mongoexport --db blogApp --collection users \
    --type=csv --fields=name,email,age \
    --out /exports/users.csv

# Export with a query
mongoexport --db blogApp --collection posts \
    --query '{"published": true}' \
    --out /exports/published-posts.json

# Export as a JSON array (instead of one document per line)
mongoexport --db blogApp --collection users \
    --jsonArray --out /exports/users-array.json

# Pretty-print JSON output
mongoexport --db blogApp --collection users \
    --pretty --out /exports/users-pretty.json

mongoimport — Import from JSON/CSV

# Import from JSON
mongoimport --db blogApp --collection users \
    --file /data/users.json

# Import from CSV (with header row)
mongoimport --db blogApp --collection users \
    --type=csv --headerline \
    --file /data/users.csv

# Import from CSV (specify fields manually)
mongoimport --db blogApp --collection users \
    --type=csv --fields=name,email,age \
    --file /data/users-no-header.csv

# Import JSON array
mongoimport --db blogApp --collection users \
    --jsonArray --file /data/users-array.json

# Upsert mode — update existing, insert new
mongoimport --db blogApp --collection users \
    --mode=upsert --upsertFields=email \
    --file /data/updated-users.json

# Drop existing collection before import
mongoimport --db blogApp --collection users \
    --drop --file /data/fresh-users.json

Automated Backup with Cron

Create a backup script and schedule it with cron:

#!/bin/bash
# /scripts/mongodb-backup.sh

TIMESTAMP=$(date +%Y%m%d_%H%M%S)
BACKUP_DIR="/backup/mongodb/$TIMESTAMP"
RETENTION_DAYS=7

# Create backup
mongodump --gzip --out "$BACKUP_DIR"

# Check if backup was successful
if [ $? -eq 0 ]; then
    echo "Backup successful: $BACKUP_DIR"
else
    echo "Backup FAILED!" | mail -s "MongoDB Backup Failed" admin@company.com
    exit 1
fi

# Delete backups older than retention period
find /backup/mongodb -type d -mtime +$RETENTION_DAYS -exec rm -rf {} +

echo "Cleanup complete. Removed backups older than $RETENTION_DAYS days."

# Schedule with cron — backup daily at 2:00 AM
crontab -e

# Add this line:
0 2 * * * /scripts/mongodb-backup.sh >> /var/log/mongodb-backup.log 2>&1

Backup Strategies

Development

• Manual backups before major changes
• mongodump to local directory

Production

• Daily automated backups with cron
• Compressed backups to save disk space
• Keep 7-30 days of retention
• Store backups off-site (S3, Google Cloud Storage)
• Test restores regularly

Upload to S3 After Backup

# Add to your backup script:
aws s3 sync "$BACKUP_DIR" "s3://my-backups/mongodb/$TIMESTAMP" --storage-class STANDARD_IA

Verifying Backups

# Always test your backups by restoring to a test environment
mongorestore --db blogApp_test --drop /backup/latest/blogApp

# Then verify the data
mongosh blogApp_test --eval "db.posts.countDocuments()"

What's Next

Your data is now protected with proper backup strategies. In the next episode, we'll integrate MongoDB with Node.js — learning how to connect, perform CRUD operations, and build a complete API using the MongoDB Node.js driver and Mongoose ODM.