That doesn't account for physical disk characteristics at all. You could have disks from different generations all be part of a pool, CMR vs SMR(!) (needs zone

That doesn't account for physical disk characteristics at all. You could have disks from different generations all be part of a pool, CMR vs SMR(!) (needs zone resets and large chunk writes), disks could degrade etc. Plus, when you update a file, you literally create new links and update the file out of place (true for any COW FS). So the read won't be sequential if you want to access two versions at the same time. In that case you want to know if you optimize for hardware failure as opposed to for performance. This could be fixed for specific usecases but not all block patterns in general. Just why I posted this.