FADU Introduces File-Semantic SSD to Move Filesystem into SSD Flash

New SSD Architecture Announced

FADU, a Seoul-based SSD controller designer, unveiled its File-Semantic SSD (FS-SSD) at the 2026 OCP Global Summit. This new technology integrates the filesystem directly within the SSD's flash memory.

The FS-SSD design allows GPUs, DPUs, and NICs to open and read files without involving the host filesystem, block layer, or storage-server CPU. This approach aims to reduce the processing burden on host CPUs.

Addressing CPU Overhead

FADU's research indicates that the filesystem and block layers can consume approximately 30% of CPU cycles during GPUDirect Storage (GDS) random-read workloads. The FS-SSD is designed to manage the control path, complementing the existing acceleration of the data path.

Preliminary tests by FADU using NFS over NVMe on a drive with their FC6161 Gen6 controller showed consistent remote file throughput of about 460,000 operations per second, even when the server scaled down to a single core. This performance contrasts with Linux NFS-over-RDMA, which achieved significantly lower operations per second with fewer cores.

Technical Implementation

The FS-SSD utilizes NFSv3, chosen for its small operation set (21 operations), OS and filesystem agnosticism, and stateless nature, which contributes to low firmware overhead. NFSv3 operations are carried within standard NVMe commands, with the drive handling path lookup, access control, and file-to-flash mapping.

The technology merges the filesystem and flash translation layer with a file layer derived from F2FS. Node and data blocks are aligned with natural flash pages and erase units, allowing the F2FS node table to function as a "File Map" pointing node IDs to physical flash addresses. This design also results in a smaller DRAM mapping metadata overhead, using approximately 0.1% of NAND capacity, similar to standard SSDs.

Availability and Future Plans

FADU stated that the FS-SSD technology is currently under active development. The company expects to provide Gen6-host results by Q1 2027 and anticipates partner samples to be available by Q3 2027.