Complete System Design Guide: Scalability, Networking, Databases, Web Communication & Messaging
Vertical Scaling vs. Horizontal Scaling
Vertical Scaling (Scaling Up): Upgrading the existing server by adding more CPU, RAM, or storage. It is simpler but has hardware limits.
Horizontal Scaling (Scaling Out): Adding more servers to distribute the load. It improves fault tolerance and scalability but requires load balancing.
Networking and Distribution
Load Balancers
Distribute traffic across multiple servers to ensure no single server is overwhelmed.
Can be software-based (Nginx, HAProxy) or hardware-based.
Types: Round-robin, Least Connections, IP Hash, etc.
Content Delivery Networks (CDN)
A network of distributed servers that cache content closer to users to reduce latency.
Examples: Cloudflare, Akamai, AWS CloudFront.
Caching
Stores frequently accessed data to reduce database queries and improve speed.
Types: Client-side (browser cache), Server-side (Redis, Memcached), CDN caching.
IP Address
A unique identifier assigned to each device on a network.
Types: IPv4 (e.g., 192.168.1.1), IPv6 (e.g., 2001:db8::ff00:42:8329).
TCP/IP
TCP (Transmission Control Protocol): Ensures reliable, ordered, and error-checked delivery.
IP (Internet Protocol): Handles addressing and routing packets.
Domain Name System (DNS)
Converts human-readable domain names (e.g., google.com) into IP addresses.
Works with caching to speed up lookups.
Web Communication
HTTP
Protocol for web communication. Uses request methods like GET, POST, PUT, DELETE.
Stateless, meaning each request is independent.
REST
Representational State Transfer (REST) is an architectural style for APIs.
Uses stateless HTTP with resources identified by URLs.
Responses often use JSON or XML.
GraphQL
A query language for APIs that allows clients to request only the data they need.
Flexible compared to REST but can be complex.
gRPC
A high-performance, language-neutral framework for RPC (Remote Procedure Calls).
Uses Protocol Buffers (protobuf) instead of JSON for efficiency.
WebSockets
A bi-directional, persistent connection between client and server.
Used for real-time applications like chat apps and live notifications.
Databases and Storage
SQL
Structured Query Language for relational databases like PostgreSQL, MySQL, SQL Server.
Uses structured schemas and tables.
ACID
Ensures database transactions are Atomic, Consistent, Isolated, Durable (ACID).
Prevents issues like data corruption.
NoSQL
Non-relational databases like MongoDB, Cassandra, DynamoDB.
Suitable for unstructured data and high scalability.
Sharding
Splitting large databases into smaller partitions (shards) to improve performance.
Each shard handles a subset of data.
Replication
Copying data across multiple servers to improve redundancy, fault tolerance, and read performance.
Types: Master-Slave, Master-Master.
CAP Theorem
Consistency, Availability, Partition Toleranceโa distributed system can only guarantee two out of three.
CP (Consistency + Partition Tolerance): MongoDB
AP (Availability + Partition Tolerance): Cassandra
Messaging and Queues
Message Queues
Asynchronous communication between services using a queue.
Prevents system overload and improves scalability.
Examples: Kafka, RabbitMQ, AWS SQS.
Let me know if you need further refinements! ๐