On Thu, Jul 01, 2021 at 12:35:53PM +0200, Martin Wilck wrote: > I respectfully disagree. Users of dm-multipath devices expect that IO > succeeds as long as there's at least one healthy path. This is a > fundamental property of multipath devices. Whether IO is sent > "normally" or via SG_IO doesn't make a difference wrt this expectation. If you have those (pretty reasonable) expections don't use SG_IO. That is what the regular read/write path is for. SG_IO gives you raw access to the SCSI logic unit, and you get to keep the pieces if anything goes wrong.