The Challenge
Log files are everywhere — SSH logs, web server access logs, application traces. They grow fast and they're expensive to store. We wanted to know: how far can we push compression on real-world log data?
We use xz -9 as our baseline — it's widely regarded as the strongest general-purpose compressor available and the standard benchmark for maximum compression.
We took a 70MB SSH syslog file (655,000 lines) and ran it through every major compressor at maximum settings. Then we ran it through Smallest.zip.
Results
| Compressor | Size | vs Original | vs xz -9 |
|---|---|---|---|
| Original | 73,417,506 (70.0 MB) | — | — |
| gzip -9 | 4,369,700 | 94.0% smaller | +20.7% |
| xz -9 | 3,619,968 (3.5 MB) | 95.1% smaller | baseline |
| bzip2 -9 | 3,211,415 | 95.6% smaller | -11.3% |
| zstd -19 | 3,002,640 | 95.9% smaller | -17.1% |
| Smallest.zip V2 | 1,596,540 (1.5 MB) | 97.8% | -55.9% |
| Smallest.zip | 1,181,418 (1.1 MB) | 98.4% | -67.4% |
Key Takeaways
Smallest.zip compresses the 70MB log file down to just 1.1MB — that's a 98.4% reduction. For context:
- It's 67% smaller than xz at maximum compression (-9)
- It's 3.7x smaller than gzip at maximum compression (-9)
- It's 2.5x smaller than zstd at its highest setting (-19)
Try It Yourself
Upload your own files at smallest.zip and see the difference. Every account starts with free credits.