java-design-patterns/sharding/README.md

---
layout: pattern  
title: Sharding 
folder: sharding  
permalink: /patterns/sharding/  
categories: Behavioral
language: en
tags:  
 - Performance
 - Cloud distributed
---  
  
## Intent  
Sharding pattern means divide the data store into horizontal partitions or shards. Each shard has the same schema, but holds its own distinct subset of the data. 
A shard is a data store in its own right (it can contain the data for many entities of different types), running on a server acting as a storage node.

## Class diagram
![alt text](./etc/sharding.urm.png "Sharding pattern class diagram")

## Applicability  
This pattern offers the following benefits:

- You can scale the system out by adding further shards running on additional storage nodes.
- A system can use off the shelf commodity hardware rather than specialized (and expensive) computers for each storage node.
- You can reduce contention and improved performance by balancing the workload across shards.
- In the cloud, shards can be located physically close to the users that will access the data.

## Credits  
  
* [Sharding pattern](https://docs.microsoft.com/en-us/azure/architecture/patterns/sharding)