On Thu, Oct 24, 2024 at 01:45:02PM -0600, Keith Busch wrote: > I'm not sure I follow this feedback. The SCSI feature is defined as a > lifetime stream association in SBC-5. So it's still a stream for SCSI, > but you want to call it "WRITE_HINT", which is not a term used in the > SCSI spec for this feature. But, you want to call it STREAM_SEPARATION > for NVMe only, even though the FDP spec doesn't use that term? What's > wrong with just calling it a generic hint support feature? The "Constrained Streams with Data Lifetimes" are called streams for political reasons but they are not. They are buckets of different data lifetimes. > I also don't see why SCSI couldn't use per-io hints just like this > enables for NVMe. The spec doesn't limit SCSI to just 5 streams, so this > provides a way to access them all through the raw block device. I don't mind passing per-I/O temperature hints to SCSI block devices. But we should not confuse a streams/FDP like streams that are different context which are assumed to be discarded together and have a concept of Stream Granularity Size or Reclaim Unit size with the data temperature hints that are at the storage level fundamentally per-I/O and just bucket into temperature group without any indication of data locality.
