I always wondered the same: Distribution algorithm for node selection and I am still wondering.
In the case above the file is small and maybe the new node selection algorithm has contributed to the outcome as well as optimizations like https://review.dev.storj.tools/c/storj/uplink/+/17523 where uploads get cancelled if they take longer than x-times the slowest of the fastest y uploads or even node exclusions like mentioned here: Automate node exclusions · Issue #7518 · storj/storj · GitHub. But I don’t know.
I see there are different situations. If uploader and downloader are the same or close, then I think this is correct.
Contrary to that there is the other situation where uploader and downloader are far apart. Think of a (movie) shooting in Australia (upload) and a the dailies are to be reviewed or processed by producer in Los Angeles. Maybe in such cases the download locations should be closer to downloader?
So I am a bit with @arrogantrabbit here. Upload should always be fast, meaning closest nodes is probably the fastest solution. But when it comes to downloads it could be that this is not always the case. If my downloaders are spread worldwide, mabye the pieces should be spread worldwide too to have the CDN-like performance. If I know my downloaders are in a specific region, maybe the pieces should be spread close to that location.
Maybe customers should be able to makes such a selection when they create a bucket to determine the spreading of the pieces.
But I do not know if there would be any gains from that in performance or resilience.