= Mongo -> services mongo *MongoDB* is a document database with the scalability and flexibility that you want with the querying and indexing that you need Classified as a NoSQL database program, MongoDB uses JSON-like documents with optional schemas. MongoDB is developed by MongoDB Inc. and licensed under the Server Side Public License (SSPL). == Main features * Ad-hoc queries ** MongoDB supports field, range query, and regular-expression searches. * Indexing ** Fields in a MongoDB document can be indexed with primary and secondary indices or index. * Replication ** MongoDB provides high availability with replica sets. * Load balancing ** MongoDB scales horizontally using sharding. * File storage ** MongoDB can be used as a file system, called GridFS, with load balancing and data replication features over multiple machines for storing files. * Aggregation ** MongoDB provides three ways to perform aggregation: the aggregation pipeline, the map-reduce function, and single-purpose aggregation methods. ** Map-reduce can be used for batch processing of data and aggregation operations. * Server-side JavaScript execution ** JavaScript can be used in queries, aggregation functions (such as MapReduce), and sent directly to the database to be executed. * Capped collections ** MongoDB supports fixed-size collections called capped collections. This type of collection maintains insertion order and, once the specified size has been reached, behaves like a circular queue. Doc origin https://en.wikipedia.org/wiki/MongoDB#Main_features[wikipedia] == Replication in MongoDB replica set is a group of mongod instances that maintain the same data set. A replica set contains several data bearing nodes and optionally one arbiter node. image::ROOT:replica-set-primary-with-two-secondaries.bakedsvg.svg[float=right] TIP: http://docs.swarmlab.io/SwarmLab-HowTos/swarmlab/docs/swarmlab/docs/hybrid/start-storage.html[swarmlab provide storage options^] === Video = intro **** TIP: Mongo in 100 Seconds video::-bt_y4Loofg[youtube] ****