On 12/13, Damien Le Moal wrote: > On 12/13/23 04:03, Jaegeuk Kim wrote: > > On 12/12, Christoph Hellwig wrote: > >> On Tue, Dec 12, 2023 at 10:19:31AM -0800, Bart Van Assche wrote: > >>> "Fundamentally broken model" is your personal opinion. I don't know anyone > >>> else than you who considers zoned writes as a broken model. > >> > >> No Bart, it is not. Talk to Damien, talk to Martin, to Jens. Or just > >> look at all the patches you're sending to the list that play a never > >> ending hac-a-mole trying to bandaid over reordering that should be > >> perfectly fine. You're playing a long term losing game by trying to > >> prevent reordering that you can't win. > > > > As one of users of zoned devices, I disagree this is a broken model, but even > > better than the zone append model. When considering the filesystem performance, > > it is essential to place the data per file to get better bandwidth. And for > > NAND-based storage, filesystem is the right place to deal with the more efficient > > garbage collecion based on the known data locations. That's why all the flash > > storage vendors adopted it in the JEDEC. Agreed that zone append is nice, but > > IMO, it's not practical for production. > > The work on btrfs is a counter argument to this statement. The initial zone > support based on regular writes was going nowhere as trying to maintain ordering > was too complex and/or too invasive. Using zone append for the data path solved > and simplified many things. We're in supporting zoned writes, and we don't see huge problem of reordering issues like you mention. I do agree there're pros and cons between the two, but I believe using which one depends on user behaviors. If there's a user, why it should be blocked? IOWs, why not just trying to support both? > > I do think that zone append has a narrower use case spectrum for applications > relying on the raw block device directly. But for file systems, it definitely is > an easier to use writing model for zoned storage. > > -- > Damien Le Moal > Western Digital Research
