ZeroFS: Log-structured filesystem designed for AWS S3 storage.

What it does

ZeroFS is a log-structured filesystem that exposes S3-compatible object storage as POSIX filesystems or block devices. It translates three protocols—NFS, 9P, and NBD (network block device)—to S3 API calls. All three servers run in a single userspace process. Data gets compressed and encrypted before upload to S3. Warm reads pull from local cache. The tool works with AWS S3, Google Cloud Storage, Azure Blob, any S3-compatible store, or local disk.

Who it is for

Developers and infrastructure teams who want to treat S3 buckets as mounted filesystems. The tool targets users running Linux, macOS, Windows, or BSD systems who need POSIX semantics. It also suits operators building distributed storage pools across multiple cloud regions or who want to stack other filesystems (like ZFS) on top of S3.

Pricing

The site does not show prices.

How it stands out

ZeroFS ships with comprehensive testing: 8,662 POSIX compliance test cases, kernel build stress tests, concurrent file-handling stressors, and Jepsen-style distributed systems testing. It includes deterministic simulation of the storage engine with crash injection and recovery verification. The tool demonstrates geo-distribution capability by mirroring ZFS pools across three S3 regions, with automatic degradation and resilver when a region becomes unreachable. It supports multiple access protocols from a single process, letting clients pick NFS for compatibility or 9P for stricter fsync durability semantics.

What a founder should check

First, verify incumbent performance and adoption. S3 FUSE clients and object storage gateways already exist; a founder should measure latency, throughput, and consistency guarantees against established solutions to understand where ZeroFS gains an edge. Second, examine the switching costs and lock-in. Users who move existing data to ZeroFS gain a POSIX interface, but migrating back or to competitors requires exporting the log-structured format; clarify how portable the stored data is. Third, assess the technical moat. The compression, encryption, and log structure are implementable by others. The real moat lies in test coverage and proven reliability at scale; a founder should verify whether ZeroFS has real production users and measurable uptime claims, or if it remains a well-tested but unproven tool.

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