How to Backup and Restore MongoDB Databases

In this tutorial, you'll learn about How to Backup and Restore MongoDB Databases. We cover key concepts, practical examples, and best practices.

The Problem

You need to back up your MongoDB database or restore it after data loss. Without a backup strategy, one corruption event or accidental drop can destroy days of work.

Quick Fix

Step 1: Create a backup with mongodump

mongodump --uri="mongodb://localhost:27017/mydb" --out=/backups/mongodb/2024-06-24

This exports all collections from mydb into a BSON dump at the specified path. Each collection gets its own .bson and .metadata.json file.

Expected output:

2024-06-24T10:00:00.000+0000    writing mydb.users to /backups/mongodb/2024-06-24/mydb/users.bson
2024-06-24T10:00:00.100+0000    done dumping mydb.users (1245 documents)

Step 2: Restore from a backup

mongorestore --uri="mongodb://localhost:27017" /backups/mongodb/2024-06-24

This reads the BSON files and inserts all documents into the target database. Collections are created if they do not exist.

Expected output:

2024-06-24T11:00:00.000+0000    preparing collections to restore from
2024-06-24T11:00:00.050+0000    restoring mydb.users from /backups/mongodb/2024-06-24/mydb/users.bson
2024-06-24T11:00:00.800+0000    done restoring mydb.users (1245 documents)

Step 3: Back up a single collection

mongodump --uri="mongodb://localhost:27017/mydb" --collection=users --out=/backups/mongodb/single

Use this when you only need one collection — it is faster and produces a smaller dump.

Step 4: Restore a single collection

mongorestore --uri="mongodb://localhost:27017/mydb" --collection=users --drop /backups/mongodb/single/mydb/users.bson

The --drop flag removes the existing collection before restoring, ensuring a clean replacement.

Step 5: Authenticated backup

mongodump --uri="mongodb://myuser:password@localhost:27017/mydb?authSource=admin" --out=/backups/mongodb/auth

Include credentials and the auth source in the connection string when authentication is enabled.

Step 6: Compress the backup

mongodump --uri="mongodb://localhost:27017/mydb" --archive=/backups/mongodb/mydb.gz --gzip

The --archive flag with --gzip produces a single compressed file instead of a directory of BSON files.

Common Errors

mongodump not found: If mongodump is not installed, install the MongoDB database tools: sudo apt install <a href="/databases/mongodb/">mongodb</a>-database-tools.

Authentication failure during dump: Add --username and --password flags or include credentials in the URI: mongodump --uri="<a href="/databases/mongodb/">mongodb</a>://user:pass@host/db".

Disk space exhausted: Backups fail silently when the disk is full. Check available space with df -h /backups before running large dumps.

Version mismatch: Restoring a dump from a newer MongoDB version into an older one fails. Ensure the source and target MongoDB versions are compatible.

Oplog-aware backups for replica sets: For point-in-time recovery, use mongodump --oplog which captures oplog entries during the dump. This allows restoring to a specific timestamp rather than just the dump time.

Handling large databases: For databases over 100 GB, mongodump may be too slow. Consider using file-system snapshots (LVM, EBS) or MongoDB Atlas backups instead.

Alternative Solutions

Use mongoexport for JSON export:

mongoexport --uri="mongodb://localhost:27017/mydb" --collection=users --out=users.json

Restore JSON with mongoimport:

mongoimport --uri="mongodb://localhost:27017/mydb" --collection=users --file=users.json

Common Errors

mongodump not found: If mongodump is not installed, install the MongoDB database tools: sudo apt install <a href="/databases/mongodb/">mongodb</a>-database-tools.

Authentication failure during dump: Add --username and --password flags or include credentials in the URI: mongodump --uri="<a href="/databases/mongodb/">mongodb</a>://user:pass@host/db".

Disk space exhausted: Backups fail silently when the disk is full. Check available space with df -h /backups before running large dumps.

Version mismatch: Restoring a dump from a newer MongoDB version into an older one fails. Ensure the source and target MongoDB versions are compatible.

Prevention

• Schedule daily backups with cron using mongodump.
• Store backups off-server (S3, rsync to another machine).
• Test restores periodically — an untested backup is no backup.
• Use --gzip to save disk space and transfer time.
• For replica sets, back up from a secondary node to avoid primary load.