>>>>> "Mike" == Mike Snitzer <snitzer@xxxxxxxxxx> writes: Mike> So are there drives like this?: Mike> 1) don't support RSOC Mike> 2) do support WRITE SAME Mike> 3) do populate VPD page with either WRITE SAME w/ discard bit set Mike> or UNMAP? Yes. But again, the fundamental issue here is not the drives. It's the controller firmware. I am not aware of a single SPI/SAS/FC drive that does not support at least WRITE SAME(10). For DIX and T10 PI I have a capabilities mask that each HBA driver fills out that tells the sd driver what the controller can do. And this is combined with whatever the drive reports to figure out whether integrity protection can be enabled. I have been contemplating doing something similar for "fancy" SCSI commands. We could have a flag in the scsi host template that controls whether the device supports WRITE SAME, EXTENDED COPY, etc. The advantage being that we do the matching at discovery time instead of once a WRITE SAME is issued. This would also permit HBA drivers to toggle the feature on a per instance basis. I.e. if "RAID controller firmware rev is lower than XYZ, do not support WRITE SAME". I'll do a PoC later today... -- Martin K. Petersen Oracle Linux Engineering -- dm-devel mailing list dm-devel@xxxxxxxxxx https://www.redhat.com/mailman/listinfo/dm-devel
