The storage engine is the primary component of MongoDB responsible for managing data. MongoDB provides a variety of storage engines, allowing you to choose one most suited to your application.
WiredTiger Storage Engine (Default)
MMAPv1 Storage Engine (Deprecated as of MongoDB 4.0)
In-Memory Storage Engine (Rarely Used)
Pluggable Storage Engine. (Customized accordingly requirement)
Click Here For More details about above mention the storage Engine.
*.Check default storage Engine.
WiredTiger better write performance.
WiredTiger Support Compression.
WiredTiger is used for snapshots and checkpoints system.
WiredTiger uses document level concurrency, where as MMAPV1 uses collection level locking (i.e table level locking).
WiredTiger is not available on Solaris platform whereas MMPAV1 is.
MMPAv1 use for databware housing.