Restoring Data using mongorestore

Restoring Data using mongorestore

mongorestore is a powerful utility provided by MongoDB to restore databases from binary backup files created using mongodump. It is essential for database recovery, migrations, or setting up staging environments from production backups.

When Do You Use mongorestore?

• Recovering from accidental data loss
• Moving data to a different environment (e.g., from development to production)
• Cloning data between MongoDB servers

Basic Syntax

    mongorestore [options] <backupFolderPath>

By default, mongorestore restores to a running instance on localhost:27017.

Example 1: Restore a Full Database

Assume you've previously created a backup using:

    mongodump --db=inventory --out=backup/

This creates a folder backup/inventory containing BSON and metadata files.

To restore it:

    mongorestore --db=inventory backup/inventory

    2025-05-01T08:15:00.123+0530    preparing collections to restore from
    2025-05-01T08:15:00.145+0530    reading metadata for inventory.products from backup/inventory/products.metadata.json
    2025-05-01T08:15:00.234+0530    restoring inventory.products from backup/inventory/products.bson
    2025-05-01T08:15:00.456+0530    finished restoring inventory.products (1000 documents)
    restore completed successfully

What Happens If the Database Already Exists?

Q: Will mongorestore overwrite an existing database?

A: Yes, by default it adds to existing collections. If you want to overwrite everything, use the --drop option.

Example 2: Restore with Drop Option

If you want to fully replace the existing database:

    mongorestore --drop --db=inventory backup/inventory

    dropped collection inventory.products
    restoring inventory.products from backup/inventory/products.bson
    finished restoring inventory.products (1000 documents)

This ensures all data is reset to what existed during the backup.

Example 3: Restoring a Specific Collection

You can also restore just one collection from the backup:

    mongorestore --db=inventory --collection=products backup/inventory/products.bson

    restoring inventory.products from backup/inventory/products.bson
    finished restoring inventory.products (1000 documents)

This is useful if you only need to recover a corrupted or deleted collection without affecting others.

Example 4: Restoring to a Remote MongoDB Server

If your MongoDB server is running remotely, specify the host and port:

    mongorestore --host=192.168.1.100 --port=27018 --db=inventory backup/inventory

Use --username and --password for authenticated servers.

Example 5: Restore All Databases from Dump

If your dump folder contains multiple databases, you can restore all at once:

    mongorestore backup/

This restores all databases that were dumped into the backup/ folder.

Frequently Asked Questions

Q: Can I restore into a different database name?

A: Yes. Use --nsFrom and --nsTo to rename namespaces:

    mongorestore --nsFrom=inventory.* --nsTo=new_inventory.* backup/inventory

Q: Is it possible to restore only documents that match a condition?

A: No, mongorestore doesn’t support filtering. You can restore to a temp DB and use aggregation or queries to copy what you need.

Summary

The mongorestore command is essential for restoring MongoDB data from binary backups. You can restore full databases, specific collections, or entire environments using various options like --db, --drop, --collection, and --host.

In the next topic, we’ll look at how to secure your MongoDB server using user authentication and roles.