Welcome to Mooncake

Welcome to Mooncake#

Mooncake

A KVCache-centric Disaggregated Architecture for LLM Serving.

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Mooncake is the serving platform for Kimi, a leading LLM service provided by Moonshot AI. Now both the Transfer Engine and Mooncake Store are open-sourced! This repository also hosts its technical report and the open-sourced traces.

🎉 Overview

Mooncake features a KVCache-centric disaggregated architecture that separates prefill and decode clusters. It also leverages underutilized CPU, DRAM, and SSD resources in GPU clusters to build a disaggregated KVCache pool.

Mooncake architecture

At the center of Mooncake is a KVCache-centric scheduler that balances effective throughput with latency-related Service Level Objectives (SLOs). In highly overloaded scenarios, Mooncake uses prediction-based early rejection to avoid wasting computation on requests that cannot meet their SLOs. Experiments show that Mooncake is especially effective for long-context workloads, achieving up to a 525% throughput increase in simulated scenarios while meeting SLOs. Under real workloads, Mooncake’s architecture enables Kimi to handle 75% more requests.

🔄 Updates

More
  • Aug 20, 2026: Mooncake is integrated into Miles as a rollout data-transfer backend for the fragmented, heterogeneous data moving between rollout and training in disaggregated RL. Blogs: KVCache.AI, lmsys.

  • Aug 17, 2026: Mooncake is integrated into Speculators as a distributed backend for multi-node online training, efficiently moves hidden-state between vLLM inference workers and Speculators trainers through RDMA, eliminating the need for massive hidden-state storage in offline training. Benchmark on GB300 NVL72.

  • Aug 5, 2026: llm-d added a Mooncake PD deployment guide, complementing its Mooncake Store tiered offloading integration for vLLM serving on Kubernetes.

  • Aug 1, 2026: Dynamo merged an event-driven Mooncake shared-cache index for SGLang HiCache routing, using Mooncake object events to track reusable KV pages in the shared pool.

  • Jul 24, 2026: FlexKV added Mooncake Store as a distributed REMOTE-tier backend, enabling content-addressed KV cache sharing alongside its existing Mooncake Transfer Engine integration.

  • Jul 12, 2026: TransferQueue added GPUDirect RDMA support for its Mooncake Store backend, enabling GPU clients to exchange RL tensors with the host-memory store through GDR.

  • May 7, 2026: 🚀 vLLM officially features Mooncake Store — a deep dive into how Mooncake’s distributed KVCache engine supercharges vLLM inference with high-throughput, memory-efficient, cross-instance KV cache sharing!

  • Apr 29, 2026: SGLang introduces RDMA-based P2P weight transfer for large-scale distributed RL using Mooncake TransferEngine, achieving 7x faster weight updates for the 1T-parameter Kimi-K2 model (53s → 7.2s) with zero-copy RDMA transfer across thousands of GPUs.

  • Apr 3, 2026: LMCache introduced a native Mooncake Store L2 adapter for multiprocess mode, connecting the LMCache MP server to the distributed KV cache pool.

  • Apr 1, 2026: The TENT technical report introduces declarative data-movement orchestration for heterogeneous interconnects, with evaluations in SGLang HiCache and checkpoint-engine workloads.

  • Mar 19, 2026: TorchSpec: Speculative Decoding Training at Scale is open sourced, using Mooncake to decouple inference and training via efficient hidden states management.

  • Mar 16, 2026: FastDeploy added Mooncake Store cache read/write support to its PD pipeline, complementing its global KV cache pooling across inference instances.

  • Mar 5, 2026: LightX2V now supports disaggregated deployment based on Mooncake, enabling encoder/transformer service decoupling with Mooncake Transfer Engine for high-performance cross-device and cross-machine data transfer. Details in blog.

  • Mar 3, 2026: verl added a Mooncake checkpoint-engine backend for peer-to-peer weight synchronization between training and rollout workers.

  • Feb 25, 2026: SGLang merged Encoder Global Cache Manager, introducing a Mooncake-powered global multimodal embedding cache that enables cross-instance sharing of ViT embeddings to avoid redundant GPU computation.

  • Feb 24, 2026: vLLM-Omni introduces disaggregated inference connectors with support for both MooncakeStoreConnector and MooncakeTransferEngineConnector for multi-node omni-modality pipelines.

  • Feb 12, 2026: Mooncake Joins PyTorch Ecosystem We are thrilled to announce that Mooncake has officially joined the PyTorch Ecosystem!

  • Jan 28, 2026: FlexKV, a distributed KV store and cache system from Tencent and NVIDIA in collaboration with the community, now supports distributed KVCache reuse with the Mooncake Transfer Engine.

  • Dec 27, 2025: Collaboration with ROLL! Check out the paper here.

  • Dec 23, 2025: SGLang introduces Encode-Prefill-Decode (EPD) Disaggregation with Mooncake as a transfer backend. This integration allows decoupling compute-intensive multimodal encoders (e.g., Vision Transformers) from language model nodes, utilizing Mooncake’s RDMA engine for zero-copy transfer of large multimodal embeddings.

  • Dec 19, 2025: Mooncake Transfer Engine has been integrated into TensorRT LLM for KVCache transfer in PD-disaggregated inference.

  • Dec 19, 2025: Mooncake Transfer Engine has been directly integrated into vLLM v1 as a KV Connector in PD-disaggregated setups.

  • Nov 07, 2025: RBG + SGLang HiCache + Mooncake, a role-based out-of-the-box solution for cloud native deployment, which is elastic, scalable, and high-performance.

  • Oct 15, 2025: SGLang introduced Mooncake EP and a collective communication backend as the foundation for fault-tolerant Elastic Expert Parallel inference.

  • Sept 18, 2025: Mooncake Store empowers vLLM Ascend by serving as the distributed KV cache pool backend.

  • Sept 10, 2025: SGLang officially supports Mooncake Store as a hierarchical KV caching storage backend. The integration extends RadixAttention with multi-tier KV cache storage across device, host, and remote storage layers.

  • Sept 10, 2025: The official & high-performance version of Mooncake P2P Store is open-sourced as checkpoint-engine. It has been successfully applied in K1.5 and K2 production training, updating Kimi-K2 model (1T parameters) across thousands of GPUs in ~20s.

  • Aug 23, 2025: xLLM high-performance inference engine builds hybrid KV cache management based on Mooncake, supporting global KV cache management with intelligent offloading and prefetching.

  • Aug 18, 2025: vLLM-Ascend integrates Mooncake Transfer Engine for KV cache register and disaggregate prefill, enabling efficient distributed inference on Ascend NPUs.

  • Jul 20, 2025: Mooncake powers the deployment of Kimi K2 on 128 H200 GPUs with PD disaggregation and large-scale expert parallelism, achieving 224k tokens/sec prefill throughput and 288k tokens/sec decode throughput.

  • Jun 20, 2025: Mooncake becomes a PD disaggregation backend for LMDeploy.

  • May 9, 2025: NIXL officially supports Mooncake Transfer Engine as a backend plugin.

  • May 8, 2025: Mooncake x LMCache unite to pioneer KVCache-centric LLM serving system.

  • May 5, 2025: Supported by Mooncake Team, SGLang release guidance to deploy DeepSeek with PD Disaggregation on 96 H100 GPUs.

  • Apr 22, 2025: LMCache officially supports Mooncake Store as a remote connector.

  • Apr 10, 2025: SGLang officially supports Mooncake Transfer Engine for disaggregated prefilling and KV cache transfer.

  • Mar 7, 2025: We open-sourced the Mooncake Store, a distributed KVCache based on Transfer Engine. vLLM’s xPyD disaggregated prefilling & decoding based on Mooncake Store will be released soon.

  • Feb 25, 2025: Mooncake receives the Best Paper Award at FAST 2025!

  • Feb 21, 2025: The updated traces used in our FAST’25 paper have been released.

  • Dec 16, 2024: vLLM officially supports Mooncake Transfer Engine for disaggregated prefilling and KV cache transfer.

  • Nov 28, 2024: We open-sourced the Transfer Engine, the central component of Mooncake. We also provide two demonstrations of Transfer Engine: a P2P Store and vLLM integration.

  • July 9, 2024: We open-sourced the trace as a JSONL file.

  • June 27, 2024: We present a series of Chinese blogs with more discussions on zhihu 1, 2, 3, 4, 5, 6, 7.

  • June 26, 2024: Initial technical report release.

📰 Blogs

The HiCache + Mooncake Store Architecture within a PD Group
Over One Trillion Tokens per Day: How Mooncake Powers Approaching.AI’s Token Factory

September 15, 2026

Over One Trillion Tokens per Day: How Mooncake Powers Approaching.AI’s Token Factory
Miles rollout data transfer with Mooncake
Mooncake for Miles: From Fragmented Rollout Data to Efficient Bulk I/O

August 20, 2026

Mooncake for Miles: From Fragmented Rollout Data to Efficient Bulk I/O
Mooncake SSD Offloading Architecture
Scaling KV Cache Beyond Memory with Mooncake SSD Offloading

July 15, 2026

Scaling KV Cache Beyond Memory with Mooncake SSD Offloading
KV Cache Hit Rate Figure
How Much KV Cache Budget Do We Need for LLM Serving?

June 26, 2026

How Much KV Cache Budget Do We Need for LLM Serving?