System Design 101 – Understanding Consistency

Hello “👋”

Welcome to another week, another opportunity to become a great DevOps and Software Engineer

Today’s issue is brought to you by DevOpsWeekly→ A great resource for devops and backend engineers. We offer next-level devops and backend engineering resources.

PS: Before we dive into the topic of today, I have some very exciting news to share with you:

I am launching a platform called Mentoraura in March-designed to help you break into tech, grow your career, and become a world-class engineer.

Mentoraura is for:
✅ Beginners who want a structured, no-BS path to mastering DevOps and software engineering
✅ Career changers looking for practical, hands-on mentorship to transition into tech ✅ Engineers who want to level up their skills and build real-world expertise

With Mentoraura, I’ll guide you through solving real business challenges, mastering in-demand technologies, and becoming a highly valuable engineer in the industry.

🔥 Join the waitlist now and be the first to access the platform when it launches! 👉 mentoraura.com

In our last episode, we discussed Reliability-the ability of a system to perform its intended function correctly and consistently over time. We used WhatsApp and Gmail as examples to explain how reliability builds user trust.

Now, let’s dive into Consistency-a concept that ensures all users see the same data, no matter when or where they access it.

What is Consistency?

Imagine you’re in a Zoom meeting with your team. One person shares their screen, but half the team sees the updated slides while the other half sees an older version. Confusing, right?

Consistency is about making sure that everyone using a system sees the same data at the same time. It’s not just about the system working; it’s about ensuring everyone is on the same page.

Why is Consistency Important?

Let’s take a real-life example: Jira. Jira is a tool used by teams to manage projects and track tasks. Imagine if two team members opened the same task in Jira, but one saw it as “In Progress” while the other saw it as “Done.” This inconsistency could lead to miscommunication, duplicated work, and missed deadlines.

For tools like Jira and Zoom, consistency is critical because:

• It prevents confusion and errors.

• It ensures everyone has the same information.

• It builds trust in the system.

How Do Businesses Achieve Consistency?

Here are a few simple strategies businesses use to make their systems consistent:

1. Synchronization: Ensuring all servers or devices have the same data at the same time. For example, Zoom syncs screen-sharing updates in real-time so everyone sees the same content.

2. Distributed Consensus Algorithms: Using algorithms like Paxos or Raft to ensure all parts of a system agree on the current state of data.

3. Atomic Operations: Making sure operations either complete fully or not at all. For example, when you update a task in Jira, it’s either fully updated for everyone or not updated at all.

4. Conflict Resolution: Handling situations where two users try to update the same data at the same time. For example, Jira might use timestamps to decide which update takes priority.

Real-Life Example: Zoom

Let’s look at Zoom. During a meeting, when someone shares their screen, everyone in the meeting sees the same content at the same time. This is consistency in action.

How does Zoom achieve this?

• It uses real-time synchronization to ensure all participants receive the same updates instantly.

• It handles network delays gracefully, so even if one participant has a slower connection, they still see the same content as everyone else.

• It ensures that actions like muting or unmuting are applied consistently across all participants.

This level of consistency is why millions of people rely on Zoom for seamless communication.

Real-Life Example: Jira

Now, let’s consider Jira. When a team member updates a task’s status, everyone on the team sees the change immediately. This consistency ensures that everyone is aligned and can make decisions based on the latest information.

How does Jira achieve this?

• It uses a centralized database to store task information, ensuring all users access the same data.

• It employs atomic operations to make sure updates are applied fully and consistently.

• It provides real-time notifications to keep everyone informed of changes.

This consistency is why teams trust Jira to manage complex projects effectively.

Consistency is the glue that holds systems together. Whether it’s Zoom ensuring everyone sees the same screen or Jira keeping task statuses aligned, consistency prevents confusion and builds trust.

In the next episode of our System Design series, we’ll dive into Partition Tolerance-what it means for a system to keep working even when parts of it fail. Stay tuned!

Until then, think about this: How would you feel if your favorite app showed you different data every time you refreshed it? That’s why consistency matters.

Got questions or thoughts? Reply to this newsletter-I’d love to hear from you!