Low-Level Design (LLD) for Web Crawler System Design
The load balancer distributes incoming requests among multiple web servers to ensure load balancing and fault tolerance.
2. Web Servers
- There are three web server instances: Web Server 1, Web Server 2, and Web Server 3.
- These web servers handle incoming requests for fetching and processing web pages.
3. Microservices (Crawling Service)
The Crawling Service is a microservice responsible for coordinating the crawling process. It consists of three components:
- Processing Service: This component processes the fetched web pages.
- Queue Service: This service manages the queue of URLs to be crawled.
- Cache Layer: This layer caches frequently accessed data to improve performance.
4. Databases
- The Databases section includes both NoSQL and relational databases for storing crawled data.
- These databases store the processed data obtained from the crawling process.
5. Additional Components
- Data Processing Pipeline: This component processes the crawled data before storing it in databases.
- Cache Layer: This layer caches data to improve system performance by reducing the load on databases.
- Monitoring Service: This service monitors the health and performance of web servers, microservices, and databases.
- API Gateway: The API Gateway serves as a central access point for external clients to interact with the microservices.
Design Web Crawler | System Design
Creating a web crawler system requires careful planning to make sure it collects and uses web content effectively while being able to handle large amounts of data. We’ll explore the main parts and design choices of such a system in this article.
Important Topics for Web Crawler System Design
- Requirements Gathering for Web Crawler System Design
- Capacity Estimation for Web Crawler System Design
- High-Level Design (HLD) for Web Crawler System Design
- Low-Level Design (LLD) for Web Crawler System Design
- Database Design for Web Crawler System Design
- Microservices and API Used for Web Crawler System Design
- Scalability for Web Crawler System Design