Love to hear that there will be more real hw tests. At the moment I am building NAS and used your benchmark for evaluating the filesystems. I am glad to see that your data roughly matches mine (apart from scrub which on 4x 6tb HDDs took 15 hours for md-raid10 while CoW systems took seconds). Personally I found that array of HDDs behaves very differently than GH runner (my feeling is that since it runs on same disk you are testing theoretical throughput rather than ability to utilize disks). My tests gave an idea for following topologies:

  * 4 HDDs (for example dm-raid has read balancing optimized specifically for HDDs)
  * 5 HDDs (classical raid should see no improvement but btrfs and bcachefs should balance the load)
  * 4 SSDs
  * 3 HDDs + 1 SSD no tiering
  * 2 HDDs + 2 SSD no tiering
  * 1 drive 10x larger than others (since how bcachefs and btrfs allocators work)
  * nocow

Thanks for awesome work