Alibaba's Open Channel SSD and Fusion Engine: A New Integrated Storage Architecture for Data Centers

With the rapid development of AI, cloud computing, big data and other applications, diverse use cases pose new challenges to data center storage devices, including:

(1) Need for more optimized performance: demand for software/hardware co-optimization.

(2) Need for greater flexibility: diverse and rapidly changing workloads require more flexibility and custom settings.

(3) Supply elasticity and cost optimization needs: continuously rising costs and supply elasticity.

(4) Performance stability and determinism: applications need to control I/O paths to achieve deterministic performance.

(5) Instant responsiveness: need faster response to online issues.

Traditional SSD standards can no longer meet the next‑generation data‑center requirements for integrated software‑hardware optimization, so Alibaba has introduced the Open Channel SSD and Fusion Engine storage engine, proposing a new integrated storage architecture.

Alibaba defined the Alibaba Open Channel (AOC) SSD specification to open low‑level hardware interfaces, allowing upper‑layer storage software to achieve maximum IO optimization flexibility. Alibaba also created the first AOC‑compliant AliFSC controller chip, enabling commercial‑scale AliFlash V3 SSDs, and collaborated with NAND vendors to improve SSD supply elasticity while expanding a white‑box SSD ecosystem with partners.

In addition to its self‑developed AliFlash SSD hardware, Alibaba built the Fusion Engine storage‑engine software. By using a full user‑space IO stack and file system, it fully exploits SSD hardware potential, introducing a user‑space device manager and an IO scheduler based on SSD performance models. This supports Alibaba Cloud’s Pangu 2.0 distributed storage at massive scale, delivering block storage ESSD with millions of IOPS, 50 % higher IOPS, five‑fold ESSD performance, over 20 × cost‑performance improvement for Redis on Flash, and, with Storage Class Memory, reduces CPU usage to one‑quarter and remote storage read latency to one‑fifth.

Fusion Engine has now evolved to version 2.0, fully enabling Storage Class Memory, AliFlash, QLC SSD, SMR, AliFPGA and other new storage media and compute‑accelerating hardware. It offers a suite of storage‑engine solutions such as AliFlash V3 ObjectStore, intelligent heterogeneous compute acceleration (USSCA), cold storage GlacierStore, tiered storage TierStore, and high‑performance integrated key‑value store USSKV, achieving end‑to‑end performance and cost optimization.