A free and open-source, distributed POSIX file system inspired by the Google File System.

Documentation · Quick start · Use cases · Website · Contact

About

LeilFS is a free and open source, distributed POSIX file system inspired by Google File System. LeilFS is being developed and maintained by the team from Leil. Designed to run on commodity hardware, LeilFS is a high-performance, scalable, and reliable file system that provides high availability, data integrity, fault tolerance, and performance on par with local file systems. It is easy to deploy and manage, and it is designed to be used in a wide range of applications, from small clusters to large data centers.

Use cases

We target the use cases below as primary and this is where we are proud to be a great fit. Contact us to learn more.

Media & video post-production Sustained sequential throughput for 4K/8K editorial workflows. Proprietary HM-SMR support, Windows client, Connect and Navigator apps, and clustered Samba.	Data lakes & AI pipelines A single POSIX namespace across nodes and JBODs. Training and analytics read directly from the file system — no object gateway in the path.
Backup & long-term retention Erasure coding keeps usable capacity high at low overhead. Predictable cost per TB on high-density commodity drives.	Research & HPC clusters Parallel access from many clients with per-directory redundancy goals, so hot and cold datasets share one deployment.

Feature list

Resilient by architecture Separated components for metadata servers (Master, Shadow, Metaloggers), data servers (Chunkservers), and Clients.

Scales linearly Add chunkservers to add capacity and throughput. Rebalancing is automatic and online.

POSIX, not almost-POSIX Real POSIX semantics, so existing applications run unmodified.

	Capability	Detail
	High availability	uRaft-based metadata failover with coordinated floating IP management for seamless continuity.
	Seamless hardware refresh and expansion	Nodes and drives can be added or replaced without interrupting client access.
	Data integrity	End-to-end data integrity with CRC verification per chunk and periodic validation operations.
	Robust redundancy	Erasure Coding (EC): Reed-Solomon EC(d, p) for high durability, supporting simultaneous server loss without data loss or service disruption. Standard replication: Simple mirroring for improved locality and performance, especially for geographically distributed deployments. Instant Copy-on-Write Snapshots: Fast and immutable snapshots enabling historical state access and safe filesystem-level rollback.
	Protocol interoperability	S3 compatibility: Supported through Versity gateway. NFS support: Full NFSv3/NFSv4 support through Ganesha plugin (FSAL). Samba/CIFS support: High performance settings for shares on top of Linux native mount points.
	Advanced ACL framework	Rich NFSv4 and POSIX ACL support for precise access management.
	POSIX and flock advisory locking	Includes byte-range locks for concurrent collaborative access.
	Granular quota management	Limits by user, group, and directory with independent caps for size and inode count.
	Fast recursive deletion	Efficient removal of large directory trees via asynchronous task-manager operations.
	Flexible media strategy	HDD, SSD, and NVMe can coexist in the same cluster with labels and goal-based placement for tiering behavior.
	Periodic scrubbing for durability	Metadata scans: Validates chunk availability and redundancy compliance. Data scrubbing: CRC-based block checking ensures ongoing data correctness.
	Automatic data rebalancing	Reclaims space and redistributes chunks when disks or servers are added or removed.

Quick start

Install Use the Installation Guide for packages, dependencies, and full installation steps.

Set up a cluster Follow the Quick Start Guide for a simple single-machine LeilFS setup.

Go further Continue with the Administration Guide for production topology and advanced configuration.

Build from source

This section assumes the required dependencies are already installed. If not, see the Installation Guide for platform-specific dependency and source-build instructions.

git clone https://github.com/leil-io/leilfs.git
cd leilfs
mkdir build
cd build
cmake ..
nice -n 16 make -j$(nproc)

We run make under nice so the build uses a lower CPU priority. The -j$(nproc) option matches the number of build jobs to your CPU core count.

Warning

A parallel build with -j$(nproc) can exhaust memory on smaller systems. If that happens, reduce the job count (for example, use -j2).

Documentation

Quick start → A working single-machine cluster in a few minutes.	Installation → Dependencies, packages and compiling from source.	Administration → Topology, goals, quotas, upgrades and day-two operations.
Architecture → Masters, Shadows, Metaloggers, Chunkservers and Clients.	NFS & clients → Ganesha FSAL, Windows and macOS clients.	Man pages → Reference documentation for commands, services, and configuration files.

Contributing

LeilFS is built in the open and we review every contribution. Start with the Contributing Guide for the workflow, coding standards and commit conventions.

The Developer Guide is a good starting point for how to setup a development environment and run tests.

1 - Find something Browse good first issues, or open one to describe what you have in mind.

2 - Build and test Follow the Quick Start to build locally, then run the test suite before opening a pull request.

3 - Open a PR Reference the issue, describe the change and what you tested. We respond on every PR.

Contact us

Join our community chat on Matrix to connect with fellow LeilFS enthusiasts, developers and users.

Ask questions: Get help, share experiences, and discuss LeilFS usage. Discuss ideas: Propose features, improvements, and best practices. Receive updates: Follow LeilFS development, releases, and community news.

#leil:matrix.org hello@leil.io leil.io

Licensing

Most of the software is licensed under GPLv3, except the Ganesha FSAL, which is licensed LGPLv3 and located under src/nfs-ganesha/. See the FSAL LICENSE file for more info.

Thank you from the LeilFS team.

_{Engineered in Estonia · © 2026 Leil Storage OÜ}