[klauspost]

(article author here)

Zstandard is good, no doubt. I didn't include compressor with entropy compression, except gzip which I added as a reference point for the ratios. After all I know it intimately after porting it to Go.

In overall terms, it does have an unavoidable bigger cost both for compression and decompression. So to have the smallest possible impact we have chosen not to go that direction (yet).

We might add it as a lifecycle option, where it compresses to zstd when the object reaches a certain age.

Furthermore the initial implementation was Snappy, so switching to S2 could be done seamless without requiring different decompressors and keep the implementation simple.

After all, the most effective way would be for the uploaded data to be compressed. The on-server compression is to catch the cases and compress them "reasonably" without taking too many resources.