Garnet – A new remote cache-store from Microsoft Research

Original Article ↗ Hacker News Discussion ↗

Performance & architecture

  • Benchmarks show Garnet’s GET throughput far exceeding Dragonfly and Redis, with comparable or better tail latencies; some infer Redis could use major optimizations.
  • Implemented in C# with extensive unsafe and low-level memory work; many see this as proof .NET can match C/C++ performance when carefully tuned.
  • Storage layer Tsavorite (forked from FASTER) offers thread scalability, tiered storage, non-blocking checkpoints, logging, transactions, and improved memory reuse.
  • Some suspect gains come more from data structures/algorithms and multithreading than from language choice alone.
  • Questions remain about where it performs poorly and how it behaves on smaller, less “beefy” instances than the 72 vCPU benchmark box.

Redis compatibility & semantics

  • Marketed as working with existing Redis clients, but API compatibility is incomplete; streams support is unclear.
  • Redis is single-threaded and fully atomic per command, whereas Garnet is multi-threaded and explicitly notes that MSET is not atomic unless expressed as a transaction. Some see this as a serious “drop-in replacement” caveat.
  • Redis is still considered “good enough” and extremely battle-tested for most use cases; many prefer to stick with it despite Garnet’s numbers.
  • Redis clustering mitigates single-threaded limitations but introduces its own complexity.

.NET ecosystem & GC discussion

  • Thread discusses how .NET and Java JITs, GC, and profiling can sometimes outperform hand-written C/C++ code, especially with polymorphism and managed memory strategies.
  • .NET’s spans, structs, unsafe pointers, and off-heap options are cited as powerful performance knobs; debate over escape analysis and stack allocation details.
  • There is disagreement about library ecosystem maturity and toolchain: some say .NET libraries are complete and high quality; others see gaps vs JVM and note heavy dependence on Visual Studio for the “best” experience.

Azure, Windows, and deployment

  • Strong interest in Garnet as a native, high-performance cache on Windows Server and Windows containers, avoiding WSL or archived Redis ports.
  • Some want it embedded in Azure App Service or similar, with node-local caches replicated to nearby nodes, arguing network hops dominate latency anyway.
  • K8s + Cilium “local redirect” patterns are mentioned as a way to get locality benefits with other caches.

Licensing, governance & trust

  • Garnet is MIT-licensed but requires a CLA; some view this as legal housekeeping, others as enabling relicensing.
  • Concerns raised about Microsoft’s patent posture and Microsoft Research projects often stalling, balanced by notes that Garnet is already used internally and could become an Azure service.
  • Several contrast Garnet’s open license with Redis’ shifting licensing and ecosystem forks, though some still trust Redis more due to history and simplicity.