System Design

Learn System Design

How to Learn System Design?

Scalability

Availability

Latency and Performance

Concurrency and Coordination

Monitoring and Observability

Resilience and Error Handling

Fault Tolerance vs. High Availability

Flashcards Review

Chapter Assessment

HTTP vs. HTTPS

TCP vs. UDP

HTTP: 1.0 vs. 1.1 vs 2.0 vs. 3.0

URL vs. URI vs. URN

What Happens When You Type a URL into the Browser

Flashcards Review

Chapter Assessment

Introduction to Real-Time Communication

What is Long-Polling?

What is WebSocket?

What are Server-Sent Events?

Difference Between Long-Polling, WebSockets, and Server-Sent Events

Flashcards Review

Chapter Assessment

Introduction to DNS

DNS Resolution Process

DNS Load Balancing and High Availability

Flashcards Review

Chapter Assessment

What is a Proxy Server?

Uses of Proxies

VPN vs. Proxy Server

Flashcards Review

Chapter Assessment

Introduction to Load Balancing

Load Balancing Algorithms

Uses of Load Balancing

Load Balancer Types

Stateless vs. Stateful Load Balancing

High Availability and Fault Tolerance

Scalability and Performance

Challenges of Load Balancers

Flashcards Review

Chapter Assessment

Introduction to API Gateway

Usage of API gateway

Advantages and disadvantages of using API gateway

Flashcards Review

Chapter Assessment

What Is an API?

What Are REST APIs?

Resources, Not Actions

HTTP Methods and Their Semantics

URL Design

Request and Response Shapes

Status Codes and Error Design

Pagination from the Consumer's View

Idempotency Keys

Versioning and Backward Compatibility

Concurrency and Conditional Requests

REST vs gRPC vs GraphQL

Flashcards Review

Chapter Assessment

What Is Rate Limiting

Rate Limiting Algorithms

Distributed Rate Limiting

Rate Limiting in Practice

Flashcards Review

Chapter Assessment

Introduction to Caching

Why is Caching Important?

Types of Caching

Cache Replacement Policies

Cache Invalidation

Cache Read Strategies

Cache Coherence and Consistency Models

Caching Challenges

Cache Performance Metrics

Flashcards Review

Chapter Assessment

What is CDN?

Origin Server vs. Edge Server

CDN Architecture

Push CDN vs. Pull CDN

Flashcards Review

Chapter Assessment

Introduction to Data Partitioning

Partitioning Methods

Data Sharding Techniques

Benefits of Data Partitioning

Common Problems Associated with Data Partitioning

Flashcards Review

Chapter Assessment

What is Redundancy?

What is Replication?

Replication Methods

Data Backup vs. Disaster Recovery

Flashcards Review

Chapter Assessment

Introduction to CAP Theorem

Components of CAP Theorem

Trade-offs in CAP Theorem

Examples of CAP Theorem in Practice

Beyond CAP Theorem

System Design Trade-offs in Interviews

Flashcards Review

Chapter Assessment

Introduction to Databases

SQL Databases

NoSQL Databases

SQL vs. NoSQL

ACID vs BASE Properties

Real-World Examples and Case Studies

SQL Normalization and Denormalization

In-Memory Database vs. On-Disk Database

Data Replication vs. Data Mirroring

Database Federation

Flashcards Review

Chapter Assessment

What are Indexes?

How a B-Tree Index Works

Types of Indexes

B-Tree vs. LSM Tree

Indexes in Distributed Systems

Flashcards Review

Chapter Assessment

Introduction to Bloom Filters

Benefits & Limitations of Bloom Filters

Variants and Extensions of Bloom Filters

Applications of Bloom Filters

Flashcards Review

Chapter Assessment

Why Quorum?

What is Quorum?

Flashcards Review

Chapter Assessment

What is Leader and Follower Pattern?

Flashcards Review

Chapter Assessment

What is Heartbeat?

Flashcards Review

Chapter Assessment

What is Checksum?

Uses of Checksum

Flashcards Review

Chapter Assessment

Introduction to Messaging System

Introduction to Kafka

Messaging patterns

Popular Messaging Queue Systems

RabbitMQ vs. Kafka vs. ActiveMQ

Scalability and Performance

Flashcards Review

Chapter Assessment

What is a Distributed File System?

Architecture of a Distributed File System

Key Components of a DFS

Flashcards Review

Chapter Assessment

What is Security and Privacy?

What is Authentication?

What is Authorization?

Authentication vs. Authorization

OAuth vs. JWT for Authentication

What is Encryption?

What are DDoS Attacks?

Flashcards Review

Chapter Assessment

Batch Processing vs. Stream Processing

XML vs. JSON

Synchronous vs. Asynchronous Communication

Push vs. Pull Notification Systems

Microservices vs. Serverless Architecture

Message Queues vs. Service Bus

Stateful vs. Stateless Architecture

Event-Driven vs. Polling Architecture

Flashcards Review

Chapter Assessment

Quiz

Importance of Discussing Trade-offs

Strong vs Eventual Consistency

Latency vs Throughput

ACID vs BASE Properties in Databases

Read-Through vs Write-Through Cache

Batch Processing vs Stream Processing

Load Balancer vs. API Gateway

API Gateway vs Direct Service Exposure

Proxy vs. Reverse Proxy

API Gateway vs. Reverse Proxy

SQL vs. NoSQL

Primary-Replica vs Peer-to-Peer Replication

Data Compression vs Data Deduplication

Server-Side Caching vs Client-Side Caching

REST vs RPC

Polling vs. Long-Polling vs. WebSockets vs. Webhooks

CDN Usage vs Direct Server Serving

Serverless Architecture vs Traditional Server-based

Stateful vs Stateless Architecture

Hybrid Cloud Storage vs All-Cloud Storage

Token Bucket vs Leaky Bucket

Read Heavy vs Write Heavy System

Quiz

System Design Interviews - A step by step guide

Functional vs. Non-functional Requirements

What are Back-of-the-Envelope Estimations?

Things to Avoid During System Design Interview

System Design Master Template

Quiz

Designing a URL Shortening Service like TinyURL

Quiz - Designing URL Shortner

Designing Pastebin

Quiz - Designing Pastebin

Designing Instagram

Quiz - Designing Instagram

Designing Dropbox

Quiz - Designing Dropbox

Designing Facebook Messenger

Quiz - Designing Facebook Messenger

Designing Twitter

Quiz - Designing Twitter

Designing Youtube or Netflix

Quiz - Designing Youtube

Designing Typeahead Suggestion

Quiz - Designing Typeahead Suggestion

Designing an API Rate Limiter

Quiz - Designing an API Rate Limiter

Designing Twitter Search

Quiz - Designing Twitter Search

Designing a Web Crawler

Quiz - Designing a Web Crawler

Designing Facebook’s Newsfeed

Quiz - Designing Facebook’s Newsfeed

Designing Yelp or Nearby Friends

Quiz - Designing Yelp or Nearby Friends

Designing Uber backend

Quiz - Designing Uber backend

Designing Ticketmaster

Quiz - Designing Ticketmaster

Dynamo: How to design a key value store?

Dynamo: Introduction

High-Level Architecture

Data Partitioning

Replication

Vector Clocks and Conflicting Data

The Life of Dynamo’s put() & get() Operations

Anti-entropy Through Merkle Trees

Gossip Protocol

Dynamo Characteristics and Criticism

Summary: Dynamo

Quiz: Dynamo

Mock Interview: Dynamo

YouTube Likes Counter

Quiz

Cassandra: Introduction

High-level Architecture

Replication

Cassandra Consistency Levels

Gossiper

Anatomy of Cassandra's Write Operation

Anatomy of Cassandra's Read Operation

Compaction

Tombstones

Summary: Cassandra

Quiz: Cassandra

Mock Interview: Cassandra

Messaging Systems: Introduction

Kafka: Introduction

High-level Architecture

Kafka: Deep Dive

Consumer Groups

Kafka Workflow

Role of ZooKeeper

Controller Broker

Kafka Delivery Semantics

Kafka Characteristics

Summary: Kafka

Quiz: Kafka

Mock Interview: Kafka

Chubby: Introduction

High-level Architecture

Design Rationale

How Chubby Works

File, Directories, and Handles

Locks, Sequencers, and Lock-delays

Sessions and Events

Master Election and Chubby Events

Caching

Database

Scaling Chubby

Summary: Chubby

Quiz: Chubby

Mock Interview: Chubby

Hadoop Distributed File System: Introduction

High-level Architecture

Deep Dive

Anatomy of a Read Operation

Anatomy of a Write Operation

Data Integrity & Caching

Fault Tolerance

HDFS High Availability (HA)

HDFS Characteristics

Summary: HDFS

Quiz: HDFS

Mock Interview: HDFS

Google File System: Introduction

High-level Architecture

Single Master and Large Chunk Size

Metadata

Master Operations

Anatomy of a Read Operation

Anatomy of a Write Operation

Anatomy of an Append Operation

GFS Consistency Model and Snapshotting

Fault Tolerance, High Availability, and Data Integrity

Garbage Collection

Criticism on GFS

Summary: GFS

Quiz: GFS

Mock Interview: GFS

BigTable: Introduction

BigTable Data Model

System APIs

Partitioning and High-level Architecture

SSTable

GFS and Chubby

Bigtable Components

Working with Tablets

The Life of BigTable's Read & Write Operations

Fault Tolerance and Compaction

BigTable Refinements

BigTable Characteristics

Summary: BigTable

Quiz: BigTable

Mock Interview: BigTable

Design Reddit

Quiz

Designing a Notification System

Quiz

Design Google calendar (Medium)

Quiz

Design a Recommendation System for Netflix

Quiz

Design Gmail

Quiz

Design Google News, a Global News Aggregator System (Medium)

Quiz

Design Unique ID Generator (Easy)

Quiz

Design Code Judging System like LeetCode (Medium)

Quiz

Design Payment System

Quiz

Design a Flash Sale for an E-commerce Site (Hard)

Quiz

Design a Reminder Alert System

Quiz

Introduction: System Design Patterns

1. Bloom Filters

2. Consistent Hashing

3. Quorum

4. Leader and Follower

5. Write-ahead Log

6. Segmented Log

7. High-Water Mark

8. Lease

9. Heartbeat

10. Gossip Protocol

11. Phi Accrual Failure Detection

12. Split Brain

13. Fencing

14. Checksum

15. Vector Clocks

16. CAP Theorem

17. PACELC Theorem

18. Hinted Handoff

19. Read Repair

20. Merkle Trees

Quiz

Summary: Dynamo

Summary: Dynamo

consistent hashing

availability

databases

gossip protocol

+3

hard
·
5 min
·Updated Aug 2026·Credit: Grokking the Advanced System Design Interview

Summary

Dynamo is a highly available key-value store that Amazon built for its own internal services. It shows how a business requirement can shape a system design: Amazon chose higher availability over strong consistency, because that is what its business needed. The design also assumes that system and hardware failures happen, not that they might happen.

Dynamo is a peer-to-peer system, with no leader and no follower nodes. Every node is equal, with the same roles and responsibilities. That symmetry is also what removes any single point of failure.

Data gets spread across the cluster using consistent hashing, automatically and without a central authority. For fault tolerance, every write also replicates to other nodes. Dynamo does that through a sloppy quorum rather than a strict majority quorum, which keeps writes available even when some usual nodes are down.

Two more mechanisms round out the reliability story. Merkle trees, hash trees used to compare two replicas branch by branch, run anti-entropy in the background.

That catches and repairs drift between replicas without waiting for a read. Different storage engines can also be plugged into a node's local storage.

Nodes learn about each other through gossip protocol, exchanging state peer to peer instead of relying on a central directory. Dynamo also stays "always writeable" through hinted handoff: another node can accept a write temporarily when the one that should hold it is down.

That commitment to always allowing writes has a cost. Because different servers can accept writes to the same object at the same time, that object can end up with multiple versions. Dynamo tracks those versions with vector clocks and tries to reconcile them automatically.

When it cannot, it hands both versions to the client application, on the idea that the client understands the object well enough to merge them.

Pulling consistent hashing, peer-to-peer communication, gossip, vector clocks, and quorums into one working system is Dynamo's real achievement. And because Amazon built it strictly for internal use, security was never part of the design.

The table below summarizes the techniques Dynamo uses and what each one provides.

<table class="tg" style="--tw-shadow:0 0 transparent; --tw-ring-inset:var(--tw-empty, ); --tw-ring-offset-width:0px; --tw-ring-offset-color:#fff; --tw-ring-color:rgba(59,130,246,0.5); --tw-ring-offset-shadow:0 0 transparent; --tw-ring-shadow:0 0 transparent; border-spacing: 0px; border-color: black; --tw-border-opacity:1; margin: 2em auto; table-layout: fixed; width: 800px; color: rgb(61, 61, 78); font-family: &quot;Droid Serif&quot;, Georgia, serif; font-size: 18px;"> <tbody style="--tw-shadow:0 0 transparent; --tw-ring-inset:var(--tw-empty, ); --tw-ring-offset-width:0px; --tw-ring-offset-color:#fff; --tw-ring-color:rgba(59,130,246,0.5); --tw-ring-offset-shadow:0 0 transparent; --tw-ring-shadow:0 0 transparent;"> <tr style="--tw-shadow:0 0 transparent; --tw-ring-inset:var(--tw-empty, ); --tw-ring-offset-width:0px; --tw-ring-offset-color:#fff; --tw-ring-color:rgba(59,130,246,0.5); --tw-ring-offset-shadow:0 0 transparent; --tw-ring-shadow:0 0 transparent;"> <td class="tg-1yw4l" style="--tw-shadow:0 0 transparent; --tw-ring-inset:var(--tw-empty, ); --tw-ring-offset-width:0px; --tw-ring-offset-color:#fff; --tw-ring-color:rgba(59,130,246,0.5); --tw-ring-offset-shadow:0 0 transparent; --tw-ring-shadow:0 0 transparent; padding: 10px 5px; border-width: 1px; border-style: solid; border-color: black; --tw-border-opacity:1; font-weight: bold; word-break: normal; hyphens: auto; font-family: Arial, sans-serif; font-size: 17px; overflow: hidden; color: black; background-color: rgb(103, 171, 159); vertical-align: top;">Problem</td> <td class="tg-1yw4l" style="--tw-shadow:0 0 transparent; --tw-ring-inset:var(--tw-empty, ); --tw-ring-offset-width:0px; --tw-ring-offset-color:#fff; --tw-ring-color:rgba(59,130,246,0.5); --tw-ring-offset-shadow:0 0 transparent; --tw-ring-shadow:0 0 transparent; padding: 10px 5px; border-width: 1px; border-style: solid; border-color: black; --tw-border-opacity:1; font-weight: bold; word-break: normal; hyphens: auto; font-family: Arial, sans-serif; font-size: 17px; overflow: hidden; color: black; background-color: rgb(103, 171, 159); vertical-align: top;">Technique</td> <td class="tg-1yw4l" style="--tw-shadow:0 0 transparent; --tw-ring-inset:var(--tw-empty, ); --tw-ring-offset-width:0px; --tw-ring-offset-color:#fff; --tw-ring-color:rgba(59,130,246,0.5); --tw-ring-offset-shadow:0 0 transparent; --tw-ring-shadow:0 0 transparent; padding: 10px 5px; border-width: 1px; border-style: solid; border-color: black; --tw-border-opacity:1; font-weight: bold; word-break: normal; hyphens: auto; font-family: Arial, sans-serif; font-size: 17px; overflow: hidden; color: black; background-color: rgb(103, 171, 159); vertical-align: top;">Advantage</td> </tr> <tr style="--tw-shadow:0 0 transparent; --tw-ring-inset:var(--tw-empty, ); --tw-ring-offset-width:0px; --tw-ring-offset-color:#fff; --tw-ring-color:rgba(59,130,246,0.5); --tw-ring-offset-shadow:0 0 transparent; --tw-ring-shadow:0 0 transparent;"> <td class="tg-1rmb8" style="--tw-shadow:0 0 transparent; --tw-ring-inset:var(--tw-empty, ); --tw-ring-offset-width:0px; --tw-ring-offset-color:#fff; --tw-ring-color:rgba(59,130,246,0.5); --tw-ring-offset-shadow:0 0 transparent; --tw-ring-shadow:0 0 transparent; padding: 10px 5px; border-width: 1px; border-style: solid; border-color: black; --tw-border-opacity:1; font-weight: bold; word-break: normal; hyphens: auto; font-family: Arial, sans-serif; font-size: 17px; overflow: hidden; color: black; background-color: rgb(197, 214, 196); vertical-align: top;">Partitioning</td> <td class="tg-rmb8" style="--tw-shadow:0 0 transparent; --tw-ring-inset:var(--tw-empty, ); --tw-ring-offset-width:0px; --tw-ring-offset-color:#fff; --tw-ring-color:rgba(59,130,246,0.5); --tw-ring-offset-shadow:0 0 transparent; --tw-ring-shadow:0 0 transparent; padding: 10px 5px; border-width: 1px; border-style: solid; border-color: black; --tw-border-opacity:1; word-break: normal; hyphens: auto; font-family: Arial, sans-serif; font-size: 17px; overflow: hidden; color: black; background-color: rgb(197, 214, 196); vertical-align: top;">Consistent Hashing</td> <td class="tg-rmb8" style="--tw-shadow:0 0 transparent; --tw-ring-inset:var(--tw-empty, ); --tw-ring-offset-width:0px; --tw-ring-offset-color:#fff; --tw-ring-color:rgba(59,130,246,0.5); --tw-ring-offset-shadow:0 0 transparent; --tw-ring-shadow:0 0 transparent; padding: 10px 5px; border-width: 1px; border-style: solid; border-color: black; --tw-border-opacity:1; word-break: normal; hyphens: auto; font-family: Arial, sans-serif; font-size: 17px; overflow: hidden; color: black; background-color: rgb(197, 214, 196); vertical-align: top;">Incremental Scalability</td> </tr> <tr style="--tw-shadow:0 0 transparent; --tw-ring-inset:var(--tw-empty, ); --tw-ring-offset-width:0px; --tw-ring-offset-color:#fff; --tw-ring-color:rgba(59,130,246,0.5); --tw-ring-offset-shadow:0 0 transparent; --tw-ring-shadow:0 0 transparent;"> <td class="tg-1yw4l" style="--tw-shadow:0 0 transparent; --tw-ring-inset:var(--tw-empty, ); --tw-ring-offset-width:0px; --tw-ring-offset-color:#fff; --tw-ring-color:rgba(59,130,246,0.5); --tw-ring-offset-shadow:0 0 transparent; --tw-ring-shadow:0 0 transparent; padding: 10px 5px; border-width: 1px; border-style: solid; border-color: black; --tw-border-opacity:1; font-weight: bold; word-break: normal; hyphens: auto; font-family: Arial, sans-serif; font-size: 17px; overflow: hidden; color: black; background-color: rgb(103, 171, 159); vertical-align: top;">High availability for writes</td> <td class="tg-yw4l" style="--tw-shadow:0 0 transparent; --tw-ring-inset:var(--tw-empty, ); --tw-ring-offset-width:0px; --tw-ring-offset-color:#fff; --tw-ring-color:rgba(59,130,246,0.5); --tw-ring-offset-shadow:0 0 transparent; --tw-ring-shadow:0 0 transparent; padding: 10px 5px; border-width: 1px; border-style: solid; border-color: black; --tw-border-opacity:1; word-break: normal; hyphens: auto; font-family: Arial, sans-serif; font-size: 17px; overflow: hidden; color: black; background-color: rgb(103, 171, 159); vertical-align: top;">Vector clocks with reconciliation during reads</td> <td class="tg-yw4l" style="--tw-shadow:0 0 transparent; --tw-ring-inset:var(--tw-empty, ); --tw-ring-offset-width:0px; --tw-ring-offset-color:#fff; --tw-ring-color:rgba(59,130,246,0.5); --tw-ring-offset-shadow:0 0 transparent; --tw-ring-shadow:0 0 transparent; padding: 10px 5px; border-width: 1px; border-style: solid; border-color: black; --tw-border-opacity:1; word-break: normal; hyphens: auto; font-family: Arial, sans-serif; font-size: 17px; overflow: hidden; color: black; background-color: rgb(103, 171, 159); vertical-align: top;">Version size is decoupled from update rates.</td> </tr> <tr style="--tw-shadow:0 0 transparent; --tw-ring-inset:var(--tw-empty, ); --tw-ring-offset-width:0px; --tw-ring-offset-color:#fff; --tw-ring-color:rgba(59,130,246,0.5); --tw-ring-offset-shadow:0 0 transparent; --tw-ring-shadow:0 0 transparent;"> <td class="tg-1rmb8" style="--tw-shadow:0 0 transparent; --tw-ring-inset:var(--tw-empty, ); --tw-ring-offset-width:0px; --tw-ring-offset-color:#fff; --tw-ring-color:rgba(59,130,246,0.5); --tw-ring-offset-shadow:0 0 transparent; --tw-ring-shadow:0 0 transparent; padding: 10px 5px; border-width: 1px; border-style: solid; border-color: black; --tw-border-opacity:1; font-weight: bold; word-break: normal; hyphens: auto; font-family: Arial, sans-serif; font-size: 17px; overflow: hidden; color: black; background-color: rgb(197, 214, 196); vertical-align: top;">Handling temporary failures</td> <td class="tg-rmb8" style="--tw-shadow:0 0 transparent; --tw-ring-inset:var(--tw-empty, ); --tw-ring-offset-width:0px; --tw-ring-offset-color:#fff; --tw-ring-color:rgba(59,130,246,0.5); --tw-ring-offset-shadow:0 0 transparent; --tw-ring-shadow:0 0 transparent; padding: 10px 5px; border-width: 1px; border-style: solid; border-color: black; --tw-border-opacity:1; word-break: normal; hyphens: auto; font-family: Arial, sans-serif; font-size: 17px; overflow: hidden; color: black; background-color: rgb(197, 214, 196); vertical-align: top;">Sloppy Quorum and Hinted Handoff</td> <td class="tg-rmb8" style="--tw-shadow:0 0 transparent; --tw-ring-inset:var(--tw-empty, ); --tw-ring-offset-width:0px; --tw-ring-offset-color:#fff; --tw-ring-color:rgba(59,130,246,0.5); --tw-ring-offset-shadow:0 0 transparent; --tw-ring-shadow:0 0 transparent; padding: 10px 5px; border-width: 1px; border-style: solid; border-color: black; --tw-border-opacity:1; word-break: normal; hyphens: auto; font-family: Arial, sans-serif; font-size: 17px; overflow: hidden; color: black; background-color: rgb(197, 214, 196); vertical-align: top;">Provides high availability and durability guarantee when some of the replicas are not available</td> </tr> <tr style="--tw-shadow:0 0 transparent; --tw-ring-inset:var(--tw-empty, ); --tw-ring-offset-width:0px; --tw-ring-offset-color:#fff; --tw-ring-color:rgba(59,130,246,0.5); --tw-ring-offset-shadow:0 0 transparent; --tw-ring-shadow:0 0 transparent;"> <td class="tg-1yw4l" style="--tw-shadow:0 0 transparent; --tw-ring-inset:var(--tw-empty, ); --tw-ring-offset-width:0px; --tw-ring-offset-color:#fff; --tw-ring-color:rgba(59,130,246,0.5); --tw-ring-offset-shadow:0 0 transparent; --tw-ring-shadow:0 0 transparent; padding: 10px 5px; border-width: 1px; border-style: solid; border-color: black; --tw-border-opacity:1; font-weight: bold; word-break: normal; hyphens: auto; font-family: Arial, sans-serif; font-size: 17px; overflow: hidden; color: black; background-color: rgb(103, 171, 159); vertical-align: top;">Recovering from permanent failures</td> <td class="tg-yw4l" style="--tw-shadow:0 0 transparent; --tw-ring-inset:var(--tw-empty, ); --tw-ring-offset-width:0px; --tw-ring-offset-color:#fff; --tw-ring-color:rgba(59,130,246,0.5); --tw-ring-offset-shadow:0 0 transparent; --tw-ring-shadow:0 0 transparent; padding: 10px 5px; border-width: 1px; border-style: solid; border-color: black; --tw-border-opacity:1; word-break: normal; hyphens: auto; font-family: Arial, sans-serif; font-size: 17px; overflow: hidden; color: black; background-color: rgb(103, 171, 159); vertical-align: top;">Anti-entropy using Merkle trees</td> <td class="tg-yw4l" style="--tw-shadow:0 0 transparent; --tw-ring-inset:var(--tw-empty, ); --tw-ring-offset-width:0px; --tw-ring-offset-color:#fff; --tw-ring-color:rgba(59,130,246,0.5); --tw-ring-offset-shadow:0 0 transparent; --tw-ring-shadow:0 0 transparent; padding: 10px 5px; border-width: 1px; border-style: solid; border-color: black; --tw-border-opacity:1; word-break: normal; hyphens: auto; font-family: Arial, sans-serif; font-size: 17px; overflow: hidden; color: black; background-color: rgb(103, 171, 159); vertical-align: top;">Synchronizes divergent replicas on the background</td> </tr> <tr style="--tw-shadow:0 0 transparent; --tw-ring-inset:var(--tw-empty, ); --tw-ring-offset-width:0px; --tw-ring-offset-color:#fff; --tw-ring-color:rgba(59,130,246,0.5); --tw-ring-offset-shadow:0 0 transparent; --tw-ring-shadow:0 0 transparent;"> <td class="tg-1rmb8" style="--tw-shadow:0 0 transparent; --tw-ring-inset:var(--tw-empty, ); --tw-ring-offset-width:0px; --tw-ring-offset-color:#fff; --tw-ring-color:rgba(59,130,246,0.5); --tw-ring-offset-shadow:0 0 transparent; --tw-ring-shadow:0 0 transparent; padding: 10px 5px; border-width: 1px; border-style: solid; border-color: black; --tw-border-opacity:1; font-weight: bold; word-break: normal; hyphens: auto; font-family: Arial, sans-serif; font-size: 17px; overflow: hidden; color: black; background-color: rgb(197, 214, 196); vertical-align: top;">Membership and failure detection</td> <td class="tg-rmb8" style="--tw-shadow:0 0 transparent; --tw-ring-inset:var(--tw-empty, ); --tw-ring-offset-width:0px; --tw-ring-offset-color:#fff; --tw-ring-color:rgba(59,130,246,0.5); --tw-ring-offset-shadow:0 0 transparent; --tw-ring-shadow:0 0 transparent; padding: 10px 5px; border-width: 1px; border-style: solid; border-color: black; --tw-border-opacity:1; word-break: normal; hyphens: auto; font-family: Arial, sans-serif; font-size: 17px; overflow: hidden; color: black; background-color: rgb(197, 214, 196); vertical-align: top;">Gossip-based membership protocol and failure detection</td> <td class="tg-rmb8" style="--tw-shadow:0 0 transparent; --tw-ring-inset:var(--tw-empty, ); --tw-ring-offset-width:0px; --tw-ring-offset-color:#fff; --tw-ring-color:rgba(59,130,246,0.5); --tw-ring-offset-shadow:0 0 transparent; --tw-ring-shadow:0 0 transparent; padding: 10px 5px; border-width: 1px; border-style: solid; border-color: black; --tw-border-opacity:1; word-break: normal; hyphens: auto; font-family: Arial, sans-serif; font-size: 17px; overflow: hidden; color: black; background-color: rgb(197, 214, 196); vertical-align: top;">Preserves symmetry and avoid centralized monitoring</td> </tr> </tbody> </table>

System design patterns

Here is a quick reference for the patterns behind Dynamo's design:

  • Consistent hashing. Dynamo uses it to spread data across nodes.
  • Quorum. A write only counts as successful once it reaches a set number of replica nodes, which keeps the data consistent.
  • Gossip protocol. Each node uses it to keep track of state information about the other nodes in the cluster.
  • Hinted handoff. Nodes use it to remember a write meant for a node that is currently down.
  • Read repair. Dynamo uses it to push the latest version of the data to nodes still holding an older one.
  • Vector clocks. Dynamo uses them to reconcile concurrent updates on the same object.
  • Merkle trees. Dynamo uses them for anti-entropy, resolving conflicts in the background.

References and further reading

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