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Distributed Systems

Foundational papers and production lessons on storage, consensus, replication, and large-scale data infrastructure — the substrate everything else runs on.

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Cassandra: What the Paper Actually Says

We had a Cassandra cluster where DELETE operations made reads progressively slower until queries timed out. Adding more disk space made it worse. The root cause is described precisely in the 2009 paper — but only if you understand that Cassandra cannot actually delete data.

Pregel: What the Large-Scale Graph Processing Paper Actually Says

PageRank in MapReduce is O(iterations × full dataset reloads). Pregel fixes this by keeping the graph in memory across iterations and replacing disk I/O with message passing. The 'think like a vertex' model is the insight — BSP is the implementation.

MapReduce: What the Google Paper Actually Says

The 2004 Google paper that gave us Hadoop — and everything that replaced it — is worth reading not for the map/reduce abstraction itself, but for the fault tolerance model and the straggler insight. The failure modes are still the failure modes.

Kafka: What the Original Paper Actually Says

The original Kafka paper from 2011 had no replication. A broker failure made all unconsumed messages permanently unavailable. The paper treats this as a limitation to fix later, not a deal-breaker. Understanding why explains more about Kafka's design philosophy than any architecture diagram.

Dapper: What Google's Distributed Tracing Paper Actually Says

Every distributed tracing tool you use — Jaeger, Zipkin, OpenTelemetry — descends from one design decision Google made in 2010: sample at the trace root, not per-span. The paper explains why, and the failure modes it didn't fully solve.

Ring Attention: What the Near-Infinite Context Paper Actually Says

Extending context beyond what fits on one GPU isn't just a memory problem — it's a communication design problem. Ring Attention sequences the K/V data through a ring of devices and hides the transfers behind computation. Here's what that actually costs in production.

MegaScale: What ByteDance's 12,288-GPU Training Paper Actually Says

At 12,288 GPUs, you see roughly one hardware failure per day. Standard training frameworks have no answer for this. MegaScale is ByteDance's account of what actually breaks when you scale LLM training to 10,000+ GPUs — and the algorithm-system co-design changes that kept MFU above 55%.

HNSW: What the Vector Similarity Search Paper Actually Says

Every vector database runs HNSW under the hood. Most engineers tune M and ef_construction without understanding what they're actually trading off. The paper rewards a close read.

GFS: What the Google File System Paper Actually Says

GFS isn't just 'distributed POSIX.' The paper is an exercise in deliberately violating POSIX to make large-scale sequential workloads tractable on unreliable hardware. The consistency model it chose — intentionally weaker than what you'd expect — defines everything downstream, including HDFS.