System design: Cassandra Architecture | Apache Cassandra Tutorial | Apache Cassandra Training | Edureka

April 24, 2021

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***** Apache Cassandra Certification Training : https://www.edureka.co/cassandra​ *****

This Edureka video on "Cassandra Architecture" will give you a detailed knowledge of architecting and creating Cassandra Database Systems. In addition, you will learn about the complex inner workings of Cassandra such as Gossip Protocol, Read Repairs and much more. Course Objectives: After the completion of 'Apache Cassandra' course at Edureka, you should be able to: 1. Understand Cassandra and NoSQL domain. 2. Create Cassandra cluster for different kinds of applications. 3. Understand Apache Cassandra Architecture. 4. Design and model Applications for Cassandra. 5. Port existing application from RDBMS to Cassandra. 6. Learn to use Cassandra with various programming languages. Who should go for this course? A developer working with large-scale, high-volume websites. An application architect or data architect who needs to understand the available options for high-performance, decentralized, elastic data stores A database administrator or database developer currently working with standard relational database systems who needs to understand how to implement a fault-tolerant, eventually consistent data store A manager who wants to understand the advantages (and disadvantages) of Cassandra and related columnar databases to help make decisions about technology strategy A student, analyst, or researcher who is designing a project related to Cassandra or other non-relational data storage options. Pre-requisites This course assumes no prior knowledge of Apache Cassandra or any other NoSQL database. Though some familiarity with Linux command line is essential, minimal exposure to Java, database or data-warehouse concepts is required. Why should you Learn Cassandra? 1. Cassandra is designed to handle Cassandra workloads across multiple data centres with no single point of failure, providing enterprises with extremely high database performance and availability. 2. World's largest Website (i.e Cassandra) is running over Cassandra. 3. Daily 100s of start-ups and large product companies are choosing Cassandra for their next generation computing and data platforms. Some companies using Cassandra are Facebook, Twitter, IBM, Cisco, Rackspace, NetFlix, eBay, Reddit, @WalmartLabs, Zoho, Digg and so on. 4. Apache Cassandra is open-source. It means you can deep dive into its source code and change it according to your own requirements. 5. The job market for Apache Cassandra is at peak and is growing at a rate of 300%!

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1. Top layer
2. Middle layer
3. Core layer

  Middle layer

• Commitlog    
• Memtable
• SSTable
• Indexes
• Compaction    

Core layer

• Messaging service
• Gossip protocol
• Cluster state
• Partitioner
• Replication    

Gossip protocol: Features

Gossip protocol is becoming increasingly popular in distributed application mainly because of these 3 features:

Simplicity, scalability, reliability 

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Write consistency levels

The write consistency level determines "how many replica nodes must respond with a success acknowledgement in order for the write to be considered successful"

Consistency level      Implication

Zero

Any

ONE

Quorum

All 

Key elements: Write path

Commit log

MemTable

SSTable 

Commit log - The commit log is a crash-recovery mechanism that supports Cassandra's durability goals

MemTable is an in-memory data structure that corresponds to a CQL table

SSTable - The contents of the memtable are flushed to disk in a file called an SSTable

Incremental repair - Google it!