On 2021/01/19 3:25, Christoph Hellwig wrote: > On Tue, Jan 12, 2021 at 07:52:27AM +0000, Damien Le Moal wrote: >>> >>> I do not understand the logic here, given that NVMe does not have >>> conventional zones. >> >> 512e SAS & SATA SMR drives (512B logical, 4K physical) are a big thing, and for >> these, all writes in sequential zones must be 4K aligned. So I suggested to >> Chaitanya to simply use the physical block size as the LBA size for the target >> to avoid weird IO errors that would not make sense in ZNS/NVMe world (e.g. 512B >> aligned write requests failing). > > But in NVMe the physical block size exposes the atomic write unit, which > could be way too large. Іf we want to do this cleanly we need to expose > a minimum sequential zone write alignment value in the block layer. > OK, good point. I think I can cook something like that today. -- Damien Le Moal Western Digital Research
