Recommended value for read concurrency for NVMe drive

I’m using restic to backup among other things many small files. I was wondering what is the recommended value for the read concurrency flag?

Probably it depends on the use case and on the hardware. For example an HDD cannot efficiently read multiple files at once so the default value of 2 might be a good choice.
However, which value should be selected for a fast NVMe drive? 8, 16, 32? Or should it be equal to the number of processor cores?

Or does it come down to simply trying and choosing what works best?


I guess you’ll have to give it a try. I’d recommend to start with something small like 4 or maybe, maybe 8 and compare that with the default value. It’s quite likely that the throughput quickly saturates, especially the compression is rather CPU-intensive for small files. In doubt, stick as close to the default values as reasonable.