@hmdsefi

Hamed Yousefi

@hmdsefiDubai, UAEJoined September 2026

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Hamed Yousefi's blogs

Hamed Yousefihmdsefi.hashnode.dev7 posts

Actors in Production: How Discord, LinkedIn and Halo Use the Actor Model

The actor model is easy to describe: small units that own their state, handle one message at a time, and talk only by messages. If you haven't met it yet, my previous article covers where it came from

4h ago · 16 min readhmdsefi.hashnode.dev

The Actor Model: Why It Was Invented and How It Works

If you have written concurrent code with threads, you know the routine. Several threads touch the same data, so you put a lock around it. Then you add a second lock, take the two in the wrong order on

2d ago · 15 min readhmdsefi.hashnode.dev

Running a DAG in parallel

Think about what happens when you run a build. You check out the code. Then you compile it and generate the docs. Then you run the tests and the linter. Some of these steps have to wait for others, an

6d ago · 6 min readhmdsefi.hashnode.dev

Cutting etcd/raft failover from 1.25 s to 343 ms, checked against 2,000 simulated leader crashes

When the leader of a three-node etcd/raft cluster dies, the other two servers wait between 1 and 1.9 seconds before one of them holds an election. That's with a tick every 100 ms and the settings from

Oct 19 · 10 min readhmdsefi.hashnode.dev

A Go test that passed 40,000 times, then lost a write under load

Say a client writes a value and gets a success back. Later, the value is gone. It happens once in production, around the time a node restarts, and every test is green. A week later a CI job fails on a

Oct 13 · 9 min readhmdsefi.hashnode.dev

Hamed Yousefi

About

Available for

Hamed Yousefi's blogs

Actors in Production: How Discord, LinkedIn and Halo Use the Actor Model

The Actor Model: Why It Was Invented and How It Works

Running a DAG in parallel

Cutting etcd/raft failover from 1.25 s to 343 ms, checked against 2,000 simulated leader crashes

A Go test that passed 40,000 times, then lost a write under load

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Hamed Yousefi

About

Available for

Hamed Yousefi's blogs

Actors in Production: How Discord, LinkedIn and Halo Use the Actor Model

The Actor Model: Why It Was Invented and How It Works

Running a DAG in parallel

Cutting etcd/raft failover from 1.25 s to 343 ms, checked against 2,000 simulated leader crashes

A Go test that passed 40,000 times, then lost a write under load