Erofs – Enhanced Read-Only File System – The Linux Kernel Documentation
8 hours ago
- #compression
- #read-only
- #filesystem
- EROFS is a read-only filesystem designed for flexibility, extendability, and performance.
- It targets read-only media and trusted solutions requiring immutability and bit-for-bit identical images.
- Features include block and file-based distribution, transparent compression, deduplication, and extended attributes.
- Compression algorithms supported: LZ4, MicroLZMA, DEFLATE, and Zstandard.
- It supports inode page sharing, large folios, direct I/O, and FSDAX for optimized performance.
- Mount options include user_xattr, acl, cache_strategy, and dax for access control and performance tuning.
- On-disk layout emphasizes simplicity with aligned metadata and data areas, using fixed and variable-sized extents.
- Directories use a compact alphabetical format for efficient random lookup.
- Chunk-based files enable data deduplication with uncompressed chunks.
- Long extended attribute name prefixes optimize storage and performance for common xattr patterns.