EROFS as a replacement for EXT4 and Squashfs
summary
EROFS is a read-only filesystem (in mainline since Linux 5.4) that supports deduplication and LZ4 and uses in-place decompression to avoid extra buffers. Android 13 Pixel experiments show 24% average size reduction (up to 45%, e.g. 3.9 GB → 2.5 GB). OTA diffs use a decompress-diff-recompress pipeline to keep delta sizes comparable to EXT4. Raw-read microbenchmarks match or beat EXT4, compressed boots run ~10–15% faster, but some app launches (Photos) incur up to 10% regressions from Kworker decompression.
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chapters (13)
- 0:00Introduction to EROFS
- 1:04Performance and compression results
- 2:06OTA system integration challenges
- 2:48Benchmarking and app launch times
- 3:51Decompression regression analysis
- 4:14Compression support and alternatives
- 5:19Btrfs as a potential alternative
- 6:01Q&A session begins
- 6:24SSD support and use cases
- 7:08Generic read-only file system design
- 8:10Btrfs for data partitions and containers
- 9:13EROFS in containers and Apex modules
- 9:55FS-verity and subvolume integrity
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