Rough expectation for compressing JSON logs?
Repetitive JSON commonly reaches 8 to 12 times with zstd, because keys repeat on every line. If you are seeing less than three, the payload is probably already encoded or encrypted somewhere inside, which is worth knowing for reasons beyond storage.
gzip, zstd or xz for archives I keep for years?
The tradeoff in one table:
| gzip | zstd | xz | |
|---|---|---|---|
| Compression | baseline | better | best |
| Speed | fast | fastest | slow |
| Decompress | fast | fastest | moderate |
| Ubiquity | everywhere | recent | common |
For long-term archives the deciding factor is not ratio but whether the format opens without installing anything in ten years, which still favours gzip for the outer layer.
Does this still hold if I am working alone?
It gets easier, not harder. A fair share of the difficulty is coordination, and that disappears. What remains is remembering your own decisions, which is what writing them down is for.