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Concept of Sharding in MongoDB 

Your application has grown. It has more daily active users, capabilities, and data production. Your database is currently acting as a restriction for the remainder of your application. Database sharding may be the remedy for your issues, but few have a solid knowledge of what it is and when it should be used. This article will delve deeper into sharding and explore the benefits and challenges of the sharding technique, the different types of sharding, and how to configure and manage sharded clusters in MongoDB.

What is Sharding?

Sharding is a technique used in distributed databases like MongoDB to partition data horizontally across multiple servers or clusters. Instead of storing all the data in a single server, data is partitioned into smaller chunks and stored across multiple servers. Each shard is responsible for storing a subset of the data. MongoDB’s query router, or mongos, is responsible for routing queries to the appropriate shard based on the query’s criteria.

The sharding technique is especially useful when working with a lump sum of datasets that cannot be arranged on a single server. Sharding allows you to scale out your database infrastructure and handle more read-and-write operations by dividing the data into smaller units and distributing them across multiple servers. 

The Scheme of Sharding in MongoDB

In a sharded MongoDB deployment, there are three main components:

  •  Shards: Shards are individual servers that store a subset of the data.
  • Config servers: Config servers keep track of the location of data in the sharded cluster.
  • Query routers: The latter is responsible for routing queries to the appropriate shard.

Benefits of Sharding

Each time you add a new shard to your MongoDB deployment, you must tell the mongos about the new shard by adding it to the cluster configuration. Once the shard is added to the cluster, MongoDB will automatically distribute data across the shards based on a shard key. The shard key is a field in MongoDB’s data to determine which shard to store the data on.

The Shard Key

In the entire process, the shard key is quintessential to the performance of a sharded MongoDB deployment. If the shard key is poorly chosen, MongoDB may end up storing most of the data on a single shard, which will abort the entire purpose of sharding. The shard key ideally must distribute the data evenly across the shards.

Management of Technique

Another important consideration when sharding a MongoDB deployment is handling data consistency. Since data is distributed across multiple shards, data can become inconsistent if a write operation fails on one shard but succeeds on another. MongoDB uses a two-phase commit protocol to prevent this to ensure that write operations are committed on all shards or rolled back on all shards.


Sharding, as implemented in MongoDB, enables the expansion of database infrastructure, facilitates the management of an increased volume of read and write operations, and enhances the overall efficacy of the MongoDB deployment. This method proves particularly valuable when dealing with voluminous datasets that cannot be accommodated within a singular server. It is imperative to judiciously select a shard key that can allocate data evenly across shards to distribute the data optimally. Additionally, data consistency is an essential concern when using sharding. MongoDB adopts a two-phase commit protocol to ensure data consistency across shards. To learn more, visit Education Nest.

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