title: “SD Algorithm”

linkTitle: “SD Algorithm”

SD algorithm

This document describes step-by-step framework on how to tackle a system design question

1. Understand the problem and establish Design Scope#

What you need to collect and define:

• Functional Requirements. They may reside in a form of User Stories or Use Cases.
• Edge Cases and Scenarios that will not be covered
• Constraints
• Architectural Characteristics for the whole system or its parts
• Borders of the system under construction

Flag: an agreement with the interviewer on the design.

Output (list of artifacts to be obtained): FR (User Stories, Corner Cases), AR+quantitative characteristics

2. Create a High-Level Design#

Sketch your main components/parts/subsystems and the connections between them. Justify, refactor and repeat.

If possible, go through a few concrete use cases.

?? Estimations

?? Define Data model (Logical and Physical ERD etc) .

=> maybe add some APIs for Read/Write scenarios for crucial components/parts then define these API and borders.

Flag: an agreement with the interviewer on the design.

Output: blueprint of a system under construction. Only main components.

3. Design Deep Dive#

identify and prioritize components in the architecture

dig deeper into 2-3 components

and select DB types

provide different approaches, their pros and cons, and why would you choose one

Flag: does your design meet all functional and non-functional requirements?

Output: ??

4. Wrapping up#

Try to answer these follow-up questions:

identify the system bottlenecks and discuss potential improvements

it could be useful to give the interviewer a recap of your design.

you can talk about error cases (network faults, server failure),

operation issues (maybe properties of production-ready systems)

how to handle next scale curve