Alpha20 keeps the alpha19 lesson: benchmark the trade-off, not just the best number.
For each row report:
- pack time v1;
- pack time v2;
- download bytes;
- chunk reuse ratio;
- estimated egress cost;
- savings vs file-level raw;
- savings vs external/measured tar.zst baseline when available.
| Profile | min / avg / max | stride | Intent |
|---|---|---|---|
| large-file-small | 64 KiB / 256 KiB / 1 MiB | 4 | maximum reuse, slower |
| large-file-balanced | 128 KiB / 512 KiB / 2 MiB | 8 | recommended default |
| large-file-large | 256 KiB / 1 MiB / 4 MiB | 16 | fastest, less precise |
Run at least:
- middle insertion;
- localized same-size overwrite;
- random rewrite 1%.
Middle insertions are CDC-friendly. Random rewrite tests are important because they prevent overclaiming.