How to Import Data Between MongoDB Instances

This guide walks you through importing data from one MongoDB instance to another. This can be helpful for migrations, backups, or syncing data. The steps are simple and user-friendly, even for beginners.

Prerequisites

Make sure you have:

• Source MongoDB instance: Where you’re exporting the data from.
• Target MongoDB instance: Where you’re importing the data to.
• MongoDB Database Tools installed, which include mongodump and mongorestore.
• Access to both MongoDB instances, either locally or remotely.

Step 1: Export Data Using mongodump

mongodump is used to export data from the source MongoDB instance into a BSON format.

Command:

mongodump --host <source_host> --port <source_port> --username <username> --password <password> \
  --authenticationDatabase <auth_db> --db <database_name> --out <output_directory>

Example:

mongodump --host 127.0.0.1 --port 27017 --db mydatabase --out ./backup

Explanation:

• --host: IP or hostname of the source MongoDB instance.
• --port: Port number of the MongoDB instance.
• --username and --password: Credentials for authentication (skip if not needed).
• --authenticationDatabase: Database used for authentication.
• --db: Name of the database to export.
• --out: Folder where the exported data will be saved.

This creates a folder (./backup) containing your database and collection files in BSON format.

Step 2: Transfer the Backup Files

If your source and target MongoDB instances are on different machines, you need to move the backup files to the target server.

Using scp:

scp -r ./backup user@target_host:/path/to/target_directory

Using rsync:

rsync -av ./backup/ user@target_host:/path/to/target_directory

Step 3: Import Data Using mongorestore

mongorestore imports the BSON dump into the target MongoDB instance.

Command:

mongorestore --host <target_host> --port <target_port> --username <username> --password <password> \
  --authenticationDatabase <auth_db> --db <database_name> <path_to_dump>

Example:

mongorestore --host 127.0.0.1 --port 27017 --db mydatabase ./backup/mydatabase

Explanation:

• --host: IP or hostname of the target MongoDB instance.
• --port: Port number of the MongoDB instance.
• --username and --password: Credentials for authentication (skip if not needed).
• --authenticationDatabase: Database used for authentication.
• --db: Name of the database to import into.
• <path_to_dump>: Path to the dump folder or specific BSON file.

Step 4: Verify the Import

After importing, verify the data in the target MongoDB instance:

1. Connect to the target instance using the CLI or a GUI like MongoDB Compass.
2. Check the imported database and collections.

Example:

mongo --host 127.0.0.1 --port 27017
> use mydatabase
> db.collection_name.find()

Bonus Tips for Advanced Users

• Export/Import Specific Collections:

  Export:

  mongodump --db mydatabase --collection users --out ./backup

  Import:

  mongorestore --db mydatabase ./backup/mydatabase/users.bson

• Overwrite Existing Data: Use --drop with mongorestore to clear existing data before importing.

  mongorestore --drop --db mydatabase ./backup/mydatabase

• Compress Files: Use --gzip to compress backup files during export and import.

  Export:

  mongodump --gzip --db mydatabase --out ./backup

  Import:

  mongorestore --gzip --db mydatabase ./backup

Conclusion

Following these steps, you can easily transfer data between MongoDB instances. Customize commands as needed for your setup and enjoy seamless data migrations!