On Mo, 2021-07-05 at 15:11 +0200, Hannes Reinecke wrote: > On 7/5/21 3:02 PM, Paolo Bonzini wrote: > > On 02/07/21 16:21, Martin Wilck wrote: > > > > SG_IO gives you raw access to the SCSI logic unit, and you get > > > > to > > > > keep the pieces if anything goes wrong. > > > > > > That's a very fragile user space API, on the fringe of being > > > useless > > > IMO. > > > > Indeed. If SG_IO is for raw access to an ITL nexus, it shouldn't > > be > > supported at all by mpath devices. If on the other hand SG_IO is > > for > > raw access to a LUN, there is no reason for it to not support > > failover. > > > Or we look at IO_URING_OP_URING_CMD, to send raw cdbs via io_uring. > And delegate SG_IO to raw access to an ITL nexus. > Doesn't help with existing issues, but should get a clean way > forward. I still have to understand how this would help with the retrying semantics. Wouldn't we get the exact same problem if a path error occurs? Regards, Martin
