The storage engine is the component of the database that is responsible for managing how data is stored, both in memory and on disk. MongoDB supports multiple storage engines, as different engines perform better for specific workloads.
- WiredTiger Storage Engine: This is the default engine. It is well-suited for most workloads and is recommended for new deployments. WiredTiger provides a document-level concurrency model, checkpointing, and compression, among other features.
- In-Memory Storage Engine: In-Memory Storage Engine is available in MongoDB Enterprise. Rather than storing documents on-disk, it retains them in-memory for more predictable data latencies.
- MMAPv1 Storage Engine: This is deprecated as of MongoDB v4.0 and is the default storage engine for MongoDB versions 3.0 and earlier.