I was wondering if the Backblaze speed test somehow used multiple threads. Watching my browser’s TCP connections with Process Explorer, I only saw two, so my guess is it’s not trying to max things with threads.
While I’m used to the IP address lacking a name that it’s known by, when I looked up the IP’s owner, it was Cloudflare instead of the Backblaze that I see during an actual backup. So you might look over this article:
Still, it’s a test and it checks at least some things. For a better test, maybe login to B2 and upload a big file?
I’ll mention that TCP uses a slow start algorithm (on purpose) so small files might never get up to full speed.
When I watch “Profiling” in the live server log, my small files never get to the bytes/second my line can do…
You’ve cited the request for parallel uploads. Larger block size might help, but I can’t give specific guidance. There might be some around, and there are certainly others who’ve commented on performance questions.
By any chance do you know if the issue is specifically Backblaze B2, or is that just the only destination run? There are plenty of possible limiting factors on speed, and it’s hard to know which ones fit a given situation.