The WiredTiger storage engine has been the default storage engine since MongoDB version 3.2. The MMAPv1 storage engine is obsolete and is no longer available in MongoDB. Among other features such as journaling, document-level concurrent model, checkpointing, WiredTiger also provides several compression algorithms to use with document collections, journals, and prefix compression for indexes. The benefit of using MongoDB compression is to save both memory and disk consumption on the database hosts.
MongoDB provides four different compressor settings:
To change the compression algorithm, edit and set the storage.wiredTiger options in /etc/mongod.conf. If the options are not explicitly set, the snappy compression is used implicitly.