SS_RL 1.3.1

Summary

This video discusses 12 key principles for creating a scalable architecture, focusing on cost reduction, availability, and scalability. It emphasizes designing with redundancy (N+1), rollback capabilities, backward compatibility, and monitoring from the outset. The principles advocate for multi-site operations, mature technologies, asynchronous communication, stateless systems, horizontal scaling, and strategic outsourcing. The video also stresses the importance of using commodity hardware and planning for scalability on multiple axes.

Takeaways

• 🔄 **Evolving Architecture**: Scalable architecture is not static; it evolves over time with changing requirements.
• 📏 **12 Principles**: There are 12 key principles for scalable architecture focusing on cost, availability, and scalability.
• 🎯 **Alignment with Goals**: Principles should align with the company's goals, vision, and mission for effectiveness.
• 📋 **Specificity and Measurability**: Principles should be clear, measurable, and avoid vague terms like 'infinite'.
• 🛠️ **Achievability and Testability**: Principles should be inspirational yet achievable and testable in design and implementation.
• 🔄 **N+1 Design**: Design with redundancy in mind; never design with less than two of anything, following the 'rule of three'.
• 🔙 **Design for Rollback**: Ensure new releases can be rolled back and are backward compatible to manage issues effectively.
• 🛑 **Design to be Disabled**: Systems should be designed to be disabled or marked down to handle risky releases.
• 📊 **Designed to be Monitored**: Incorporate monitoring from the design phase, not as an afterthought.
• 🌐 **Multiple Life Sites**: Avoid single-site solutions; design for multiple live sites to ensure continuity and reduce failover time.
• 🛠️ **Use Mature Technologies**: Opt for tried and tested technologies over new ones to avoid being the first to encounter bugs.
• 📬 **Asynchronous Design**: Communicate asynchronously by default to increase fault tolerance and scalability.
• 🏦 **Stateless Systems**: Use state only when necessary as it can impact scalability, availability, and cost.
• 🌐 **Scale Out, Not Up**: Focus on horizontal scaling rather than relying on larger, more expensive hardware.
• 🔄 **Design for Scalability**: Plan for scalability on at least two axes to accommodate future growth.
• 🛒 **Non-Core Functions**: If not a core strength, consider buying non-core functions rather than building them.
• 💻 **Commodity Hardware**: Prefer cheaper, commodity hardware that is affordable, easy to maintain, and readily available.

Q & A

What are the key principles for a scalable architecture?

The key principles for a scalable architecture include designing with a minimum of n+1, ensuring rollback capabilities, designing for backward compatibility, designing to be disabled, designing to be monitored, considering multiple life sites, using mature technologies, adopting asynchronous design, preferring stateless systems, scaling out rather than up, designing for at least two axes of scalability, focusing on core competencies, and opting for commodity hardware.

Why is the n+1 design principle important?

The n+1 design principle is important because it ensures continuity during outages, failures, and maintenance by having at least two of any component, allowing for redundancy and preventing single points of failure.

What does it mean to design for rollback?

Designing for rollback means ensuring that any release of functionality can be reversed or reverted if issues arise, which is crucial for maintaining system stability and reliability.

Why is backward compatibility significant in system design?

Backward compatibility is significant because it allows new versions of a system to work with older versions, ensuring that updates do not disrupt existing functionalities or user experiences.

How does designing systems to be disabled improve fault tolerance?

Designing systems to be disabled allows for the safe deactivation of components in case of issues, providing additional time to fix problems without affecting the entire system and improving overall fault tolerance.

What is the significance of designing systems to be monitored from the outset?

Designing systems to be monitored from the beginning ensures that all aspects of the system's performance can be tracked and analyzed, which is crucial for identifying and addressing issues proactively.

Why is it recommended to avoid single-site solutions?

Single-site solutions can be risky as they create a single point of failure. It is recommended to have multiple live sites to ensure high availability and quick disaster recovery.

What advantages does using mature technologies offer?

Using mature technologies offers the advantage of reliability and stability, as they have been tested and proven over time, reducing the risk of encountering unforeseen bugs or issues.

How does asynchronous design contribute to system scalability?

Asynchronous design contributes to system scalability by allowing systems to handle failures more gracefully and by not relying on immediate responses, which can improve fault tolerance and load handling.

What are the trade-offs of using stateful systems?

Stateful systems can offer the benefit of maintaining user context and session information, but they come at the cost of reduced scalability, increased complexity, and potentially higher costs due to the need for additional resources to manage state.

Why is it advised to scale out rather than scale up?

Scaling out, or horizontal scaling, allows for more flexible and cost-effective growth by adding more machines or resources as needed, rather than relying on larger, more expensive hardware that may limit growth.

What does designing for at least two axes of scalability entail?

Designing for at least two axes of scalability means planning for the system to grow in multiple dimensions, such as data, transactions, or customers, to ensure that there is room for unexpected growth and to avoid the need for complete re-architecting.

Why is focusing on core competencies important in system design?

Focusing on core competencies ensures that a company invests its resources in areas where it can add the most value and differentiate itself from competitors, rather than trying to excel in every aspect.

What is the rationale behind preferring commodity hardware?

Preferencing commodity hardware is based on the idea that affordable, easily maintainable, and widely available hardware can reduce costs and complexity, allowing for easier scalability.