Architecture of StackOverflow - how it works 'under the hood'? (video, 4 minutes)
Today, ByteByteGo aims to set the record straight about the unexpected world of Stack Overflow's system architecture. One might believe they have the ideal code for designing a platform that manages 2 billion page views each month, but what Stack Overflow truly does might come as a surprise. Picture being tasked with creating the Stack Overflow website. One would suggest on-premise servers and a monolithic application, only to see raised eyebrows from fellow engineers. Yet, that's precisely how Stack Overflow operates. You would assume that a platform like Stack Overflow would follow prevailing tech trends. A typical big tech software engineer might sketch a system employing microservices, breaking the system into manageable chunks, each with its own database. This would demonstrate extensive use of caching, sharded services, and asynchronous communication through message queues. Some might even flaunt a bit with event sourcing combined with CQRS. And who wouldn't seize the opportunity to sprinkle in distributed system concepts like eventual consistency and the CAP theorem? Impressive, right? But here’s the twist; none of these elements appear in Stack Overflow's design. In a tech world saturated with microservices, Kubernetes, and cloud solutions, Stack Overflow stands out as an anomaly. Rather than adopting trends, they’ve kept an architecture that fits their unique circumstances best. With a single monolithic application managing the main Q&A sites, they defy our preconceived notions about designing large-scale systems. Contrary to general belief, Stack Overflow runs a monolithic application on just nine on-premise web servers. They don’t rely on the cloud or break their applications into microservices. Yet, they manage to efficiently handle enormous traffic using their unconventional approach. Instead of planning for relentless change, they've constructed a system optimized for low latency and proper memory allocation. These servers operate at a comfortable 5-10% capacity, allowing ample room for growth. And even though 80% of their traffic is anonymous - users who arrive, find a solution, and leave - they maintain astonishing performance. Even their most visited page, the questions show page, is not cached, yet it renders swiftly in just 20 milliseconds. This exceptional performance is powered by a massive 1.5 terabytes of RAM on their SQL server instances, enabling rapid access to a third of their entire database stored in memory. This success invites us to ponder, what if the most hyped tech concepts are not always the best solutions? What if the key to strong system design lies in a deeper understanding of specific challenges rather than chasing the latest trends? Stack Overflow's story serves as a striking case study, reminding us that technology isn't a one-size-fits-all field. What works for one may not work for another, underlining the importance of aligning system architecture with specific business and technical needs rather than blindly following industry trends. The tale of Stack Overflow exemplifies efficiency, practicality, and breaking stereotypes - a true testament to the power of thinking outside the box. Users will surely enjoy their videos, and they might also find interest in their system design newsletter. Covering topics and trends in large-scale system design, it's trusted by 400,000 readers. They encourage subscriptions at blog.bybygo.com.
Toggle timeline summary
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Introduction to Stack Overflow's system architecture.
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Discussing the unexpected design choices of Stack Overflow.
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Explanation of how Stack Overflow differs from typical tech trends.
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Highlighting the absence of microservices in Stack Overflow's design.
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Discussion on the monolithic application handling Q&A on Stack Overflow.
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Handling of traffic with on-premise web servers.
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Optimization for low latency and efficient memory allocation.
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Maintaining performance despite high traffic.
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Fast rendering times for high-traffic pages.
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SQL server capabilities supporting swift database access.
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Stressing the importance of tailored system architecture.
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Conclusion emphasizing Stack Overflow's efficiency and practical design.
Transcription
Today, we are setting the record straight as we dive into the unexpected world of Stack Overflow system architecture. You might think you've cracked the code to designing a platform that serves 2 billion page views a month, but what Stack Overflow does in reality might surprise you. Imagine being tasked with designing the Stack Overflow website. You suggest on-premise servers and a monolithic application, only to get raised eyebrows from your fellow engineers. Yet, this is precisely how Stack Overflow functions. You would expect a platform like Stack Overflow to mimic prevailing trends. A typical big tech software engineer might sketch a system with microservices, breaking the system into manageable chunks, each with its own database. It would show extensive use of caching, sharded services, and asynchronous communication through message queues. Some may even show off a bit with event sourcing, paired with CQRS. And who wouldn't seize the chance to sprinkle in some distributed system concepts like eventual consistency and the CAP theorem? Impressive, right? But there's the tryst. None of these elements feature in Stack Overflow's design. In a tech world saturated with microservices, Kubernetes, and cloud-based solutions, Stack Overflow stands as an anomaly. Instead of following trends, they've stuck to an architecture that best fits their unique circumstances. With a single monolithic application handling the main Q&A sites, they challenge our preconceptions about designing large-scale systems. Against popular belief, Stack Overflow operates with a monolithic application running just nine on-premise web servers. They don't rely on the cloud or break their applications into microservices. Yet they efficiently handle tremendous traffic with their unconventional approach. Instead of planning for relentless change, they've designed a system optimized for low latency and memory allocation. These servers run at a comfortable 5-10% capacity, leaving plenty of space for growth. And despite 80% of the traffic being anonymous, that is, users who land, find a solution, and leave, they maintain an astonishing performance. Even their most visited page, the questions show page, is not cached, yet it renders in a swift 20 milliseconds. This exceptional performance is powered by a massive 1.5 terabytes of RAM on their SQL server instances, enabling fast access to a third of their entire database in memory. This success prompts us to question, what if the most hyped tech concepts aren't always the best solution? What if the key to robust system design lies in a deeper understanding of specific challenges, rather than chasing the latest trends? Stack Overflow's story is a striking case study that reminds us that technology isn't a one-size-fits-all field. What works for one may not work for another, emphasizing the need to align system architecture with specific business and technical needs, rather than blindly following industry trends. Stack Overflow's story is one of efficiency, practicality, and defying stereotypes, a true testament to the power of thinking outside the box. You will like our videos. You might like our system design newsletter as well. It covers topics and trends in large-scale system design, trusted by 400,000 readers. Subscribe at blog.bybygo.com.