On 2024/9/26 16:10, Ariel Miculas wrote:
On 24/09/26 09:04, Gao Xiang wrote:
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And here [4] you can see the space savings achieved by PuzzleFS. In short, if you take 10 versions of Ubuntu Jammy from dockerhub, they take up 282 MB. Convert them to PuzzleFS and they only take up 130 MB (this is before applying any compression, the space savings are only due to the chunking algorithm). If we enable compression (PuzzleFS uses Zstd seekable compression), which is a fairer comparison (considering that the OCI image uses gzip compression), then we get down to 53 MB for storing all 10 Ubuntu Jammy versions using PuzzleFS. Here's a summary: # Steps * I’ve downloaded 10 versions of Jammy from hub.docker.com * These images only have one layer which is in tar.gz format * I’ve built 10 equivalent puzzlefs images * Compute the tarball_total_size by summing the sizes of every Jammy tarball (uncompressed) => 766 MB (use this as baseline) * Sum the sizes of every oci/puzzlefs image => total_size * Compute the total size as if all the versions were stored in a single oci/puzzlefs repository => total_unified_size * Saved space = tarball_total_size - total_unified_size # Results (See [5] if you prefer the video format) | Type | Total size (MB) | Average layer size (MB) | Unified size (MB) | Saved (MB) / 766 MB | | --- | --- | --- | --- | --- | | Oci (uncompressed) | 766 | 77 | 766 | 0 (0%) | | PuzzleFS uncompressed | 748 | 74 | 130 | 635 (83%) | | Oci (compressed) | 282 | 28 | 282 | 484 (63%) | | PuzzleFS (compressed) | 298 | 30 | 53 | 713 (93%) | Here's the script I used to download the Ubuntu Jammy versions and generate the PuzzleFS images [6] to get an idea about how I got to these results. Can we achieve these results with the current erofs features? I'm referring specifically to this comment: "EROFS already supports variable-sized chunks + CDC" [7].
Please see https://erofs.docs.kernel.org/en/latest/comparsion/dedupe.html Total Size (MiB) Average layer size (MiB) Saved / 766.1MiB Compressed OCI (tar.gz) 282.5 28.3 63% Uncompressed OCI (tar) 766.1 76.6 0% Uncomprssed EROFS 109.5 11.0 86% EROFS (DEFLATE,9,32k) 46.4 4.6 94% EROFS (LZ4HC,12,64k) 54.2 5.4 93% I don't know which compression algorithm are you using (maybe Zstd?), but from the result is EROFS (LZ4HC,12,64k) 54.2 PuzzleFS compressed 53? EROFS (DEFLATE,9,32k) 46.4 I could reran with EROFS + Zstd, but it should be smaller. This feature has been supported since Linux 6.1, thanks. Thanks, Gao Xiang
