>>>>> "Mike" == Mike Snitzer <snitzer@xxxxxxxxxx> writes: I agree that it would be great to revisit these topics at the workshop. Mike> One nagging sticking point for some storage vendors is the Linux Mike> requirement that a LUN advertise itself as SPC-3 compliant (in Mike> order for Linux's SCSI layer to issue a READ CAPACITY 16, etc). Yeah, many vendors stick to reporting compliance with really old revisions to prevent legacy operating systems from blowing up. However, for arrays I don't think it would be unreasonably hard to report a different rev. if the Linux personality is set for a given LUN. I also think it's time to get with the program for many of these vendors. SPC-3 is about 6 years old at this point. Not exactly a spring chicken... However, the SCSI folks are vehemently against having heuristics in the first place (guess how many USB-ATA bridge vendors actively participate in T10). T10's official policy is that the device can fail any command with any (valid) arguments at any time. And that the OS stack should always retry with less data, try a different command variant, etc. That might be another good topic for discussion, actually. Because while we do have some hacks in place (use_10, etc.) things will soon get more complex. Mike> Discard is more sexy so I'd expect a bit more discussion for that Mike> topic. Yeah, I'm about to post another TP update with the changes that were just approved. Mike> And again, BLOCK LIMITS VPD PAGE requirements have kept some Mike> vendors from implementing UNMAP support (sticking with WRITE SAME Mike> w/ UNMAP bit set). That's fine. We can't currently benefit from UNMAP anyway. And we're about to get better metrics for WRITE SAME. -- Martin K. Petersen Oracle Linux Engineering -- To unsubscribe from this list: send the line "unsubscribe linux-fsdevel" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
