DEV Community

Cover image for Rust Was Not the Silver Bullet I Expected for Our Server Growth
pretty ncube
pretty ncube

Posted on

Rust Was Not the Silver Bullet I Expected for Our Server Growth

The Problem We Were Actually Solving

I still remember the day our server load increased by a factor of 5 due to an unexpected surge in user traffic. Our Veltrix-powered Treasure Hunt Engine, which had been humming along smoothly until then, started to show signs of strain. Latency numbers began to creep up, and we started to notice an alarming increase in allocation counts. Our profiler output revealed a disturbing trend: the majority of the latency was due to garbage collection pauses in the Java Virtual Machine. This was not what I had expected, given that our system was designed to handle high concurrency. As I dug deeper into the issue, I realized that our choice of language and runtime was the root cause of the problem. The constant stop-the-world pauses were killing our responsiveness and throughput.

What We Tried First (And Why It Failed)

My initial instinct was to try to optimize the Java code, hoping to reduce the allocation rates and thereby decrease the frequency of garbage collection pauses. I spent countless hours poring over the code, identifying and fixing performance bottlenecks, and tweaking the JVM settings to improve performance. However, despite my best efforts, the results were underwhelming. The latency numbers did improve slightly, but the allocation counts remained stubbornly high. It became clear that we were fighting a losing battle, and that a more fundamental change was needed. I decided to investigate alternative languages and runtimes that could provide better performance and memory safety.

The Architecture Decision

After careful evaluation, I decided to migrate our Treasure Hunt Engine to Rust. I was drawn to Rust's focus on memory safety and performance, and I was impressed by the language's ability to generate highly optimized machine code. However, I was also aware of the potential drawbacks, including the steep learning curve and the limited number of libraries and frameworks available. Despite these concerns, I believed that the benefits of using Rust outweighed the costs. I assembled a team of engineers and we began the process of porting the code to Rust. It was a challenging and time-consuming process, but ultimately it paid off. Our new Rust-based engine was a significant improvement over the old Java-based one, with latency numbers reduced by a factor of 3 and allocation counts almost eliminated.

What The Numbers Said After

The numbers told a compelling story. Our profiler output showed that the Rust-based engine was spending almost no time in garbage collection, and the allocation counts were negligible. The latency numbers were also dramatically improved, with 99th percentile latency reduced from 500ms to 150ms. But what really caught my attention was the significant reduction in memory usage. Our Rust-based engine was using less than half the memory of the old Java-based engine, which was a huge win for us. We were able to handle the same workload with fewer servers, which resulted in significant cost savings. I was also impressed by the reliability and stability of the Rust-based engine. We experienced far fewer crashes and errors, and the system was much more resilient to errors and exceptions.

What I Would Do Differently

In hindsight, I would do several things differently. First, I would have started evaluating alternative languages and runtimes much earlier. I would have also invested more time and resources in training and educating my team on Rust and its ecosystem. The learning curve was steeper than I expected, and it took us longer than anticipated to get up to speed. Additionally, I would have been more careful in selecting the libraries and frameworks to use. Some of the Rust libraries we chose turned out to be immature or poorly maintained, which caused us significant headaches. Despite these challenges, I am glad we made the switch to Rust. It was not a silver bullet, but it was a crucial step in improving the performance and reliability of our Treasure Hunt Engine.

Top comments (0)