Pureonyxzip Best (2027)

| Compressor | Speed (create) | Decomp speed | Ratio | Use case | |------------|----------------|--------------|-------|-----------| | zstd:3 | 500 MB/s | 1200 MB/s | 2.5× | Fast incremental backups | | zstd:19 | 20 MB/s | 800 MB/s | 3.8× | Release artifacts | | brotli:11 | 8 MB/s | 300 MB/s | 4.2× | Web assets (pre-compressed) | | lz4 | 2000 MB/s | 3000 MB/s | 1.8× | Real-time streaming |

| Block size | Dedup efficiency | Random access overhead | Compression ratio | |------------|----------------|------------------------|-------------------| | 4 KiB | Excellent | High (more blocks) | Poor (per-block overhead) | | 64 KiB | Sweet spot | Good | Good | | 1 MiB | Reduced | Excellent | Best (dictionary reuse) |

Rule: Match block size to your filesystem’s cluster size or VM page size. pureonyxzip best

POZ provides a C API and a Rust crate for custom tooling:

// Open archive for random reads
poz_archive* arch = poz_open("archive.poz", POZ_READ);
poz_block_iterator* it = poz_iter_blocks(arch);
poz_hash hash;
while (poz_next_block(it, &hash)) 
    uint8_t* data;
    size_t len;
    poz_decompress_block(arch, &hash, &data, &len);
    // process block
    poz_free(data);

Rust example (async, with tokio):

use pureonyxzip::Archive, BlockCache;
#[tokio::main]
async fn main() -> Result<(), Box<dyn std::error::Error>> {
let archive = Archive::open("backup.poz").await?;
let mut cache = BlockCache::new(128); // LRU, 128 blocks
let contents = archive.read_file("config.json", &mut cache).await?;
println!("{}", String::from_utf8(contents)?);
Ok(())
}

pureonyxzip create backup.onx ./data -p best --encrypt --kms arn:aws:kms:... --threads 12
pureonyxzip list backup.onx
pureonyxzip extract backup.onx path/to/large.mov --out ./partial --range 0:10MB
pureonyxzip mount backup.onx /mnt/onyx

| Feature | POZ | gzip | zstd | 7z | |---------|-----|------|------|-----| | Block deduplication | ✅ | ❌ | ❌ | ❌ | | Seekable without index | ✅ (O(log n)) | ❌ | ❌ | ✅ (solid blocks) | | Parallel decompression | ✅ | ❌ | ✅ | ❌ | | Archive-in-archive support | ✅ (transparent) | ❌ | ❌ | ❌ | | Max compression ratio | 40-60% better than gzip -9 for binaries | baseline | faster, worse ratio | close, no dedup |

poz mount out.poz /mnt --readonly --cache 512 | Compressor | Speed (create) | Decomp speed