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poc-datacollector/modules/ROOT/pages/index-mongo.adoc

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 =  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
+
+A 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^]