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Please be advised: As of June 1, 2016, Scalr has deprecated support for MongoDB Automated Roles.

Table of Contents

About MongoDB 


Shard clusters include three basic components:


ShardsConfig ServersMongos Routers
These run the mongod process (the core MongoDB database process) or a Replica Set of mongod processes (see previous section). They store the data in the form of chunks (partitions of the dataset corresponding to a given range over the shard key).Processes that hold the meta data of the cluster (location and range of the different partitions or chunks). Chunk information is the main data stored by config Servers. Scalr automatically configures the config Servers on the first node (0-0) of the cluster.*Processes that route queries and balances chunks over Shards. mongos (pronounce mongo "S") are lightweight processes that can be run on any desired Server. Scalr automatically places them on the first and second node of each Shard. mongos processes do not have any persistent state: they inherit it from the config Servers.


Two Storage Types are available for your MongoDB databases. To select your storage for your MongoDB databases, go to Main MenuFarms > Select your Farm > Actions Button (rightmost column) > Configure > Click on the MongoDB Role > MongoDB Settings.