On Tue, Jul 29, 2025 at 08:13:31AM +0200, Hannes Reinecke wrote: > > > Note that chunk_sectors limit is the *stripe* size, not per drive stride. > > > Beware of the wording here to avoid confusion (this is all already super > > > confusing !). > > > > This is something we're not in the same page :( For example, 8 disks > > raid5, with default chunk size. Then the above calculation is: > > > > 64k * 7 = 448k > > > > The chunksize I said is 64k... > > Hmm. I always thought that the 'chunksize' is the limit which I/O must > not cross to avoid being split. > So for RAID 4/5/6 I would have thought this to be the stride size, > as MD must split larger I/O onto two disks. > Sure, one could argue that the stripe size is the chunk size, but then > MD will have to split that I/O... Yah, I think that makes sense. At least the way nvme uses "chunk_size", it was assumed to mean the boundary for when the backend handling will split your request for different isolated media.
