Last checked and updated on 10 Jun 2026
What Is New in MongoDB 3.1
MongoDB 3.1 delivers a major step forward with its pluggable storage engine API, WiredTiger integration, and enhanced security features. This release fundamentally changes how you manage data compression and concurrency.
| Category | Key Changes |
|---|---|
| New Features | Pluggable Storage Engine API, WiredTiger Engine, Encrypted Storage Engine, Audit System |
| Improvements | Enhanced Concurrency, Improved Compression, Better MMAPv1 Performance |
| Security | SSL Encrypted Connections by Default, LDAP Authorization Support |
| Deprecations | Deprecated MongoDB Management Service (MMS) |
How does the pluggable storage engine API change database architecture?
The pluggable storage engine API is the cornerstone of MongoDB 3.1. It allows different storage engines to be plugged into the database, each optimized for specific workloads.
This means you can now run multiple storage engines within a single deployment. In practice, this gives developers unprecedented flexibility to choose the right engine for indexing, compression, or concurrency needs on a per-collection basis.
What performance gains does the WiredTiger engine offer?
WiredTiger introduces document-level concurrency control and native compression. This is a massive upgrade from the collection-level locking in the default MMAPv1 engine.
You get significant improvements in write throughput and more efficient storage. WiredTiger supports both Snappy and zlib compression, which can reduce your data footprint by up to 80%.
Is encrypted storage now built into MongoDB?
Yes, MongoDB 3.1 includes an encrypted storage engine. This engine encrypts data on disk, including indexes and journaling files, providing encryption-at-rest.
This matters because it secures your data without requiring application-level changes. The encryption keys are managed through a separate Key Management Interoperability Protocol (KMIP) server.
How are connections secured in this release?
SSL-encrypted connections are now configured by default for all internal communications in a cluster. This ensures that data moving between mongod instances is always encrypted.
This closes a previous gap where you had to manually configure SSL for intra-cluster traffic. It™s a straightforward win for securing distributed deployments out of the box.
What auditing capabilities were added?
A new database auditing system allows you to track and log operations on the database. You can audit authorization successes and failures, schema operations, and more.
The audit events are written to a file, syslog, or the console in JSON format. This is essential for environments that need a verifiable trail of database activity.
FAQ
Can I use both WiredTiger and MMAPv1 in the same replica set?
Yes. The pluggable storage engine API allows you to assign a different engine to each collection. This lets you migrate gradually or use each engine for its strengths.
Does the encrypted storage engine impact performance?
There is a CPU overhead for encryption/decryption operations, but for many workloads, the performance impact is acceptable given the security benefit. Benchmark with your specific data.
Is the audit feature available in the Community Edition?
No. The auditing system is an enterprise-only feature available in the MongoDB Enterprise Server.
How do I switch an existing collection to use WiredTiger?
You can't directly convert a collection's storage engine. The standard method is to dump the data from the MMAPv1 collection and restore it into a new collection that uses WiredTiger.
What happens to the deprecated MMS?
MMS (MongoDB Management Service) is replaced by Cloud Manager. You should plan to migrate your monitoring and backup automation to the new Cloud Manager platform.