"Martin K. Petersen" <martin.peter...@oracle.com> writes: > Dmitry Monakhov <dmonak...@openvz.org> writes: > > Dmitry, > >> scsi_debug has very strange structure from one point it supports >> dynamic number of devices but from other point context is common for >> all devices: > >> So basically we may have many devices with single context which refers >> common data. Are any sane reason to share context between devices? >> Who use such behaviour? > > As the name implies, scsi_debug was conceived to debug the SCSI layer. > Among other things, the intent was to be able to test hundreds of > controllers and LUNs without having physical hardware or storage to back > that up. Plus to have a target whose reporting could easily be tweaked > to test the SCSI core code. > > So that's the reason for the oddball shared buffer setup. scsi_debug > wasn't really meant to be a "useful" storage target. > > If you want something with a per-device backing store I suggest you look > at the SCSI target subsystem. With tcm_loop and ramdisk you get > essentially the same thing as scsi_debug. With the added bonus that you > can use files or block devices if you actually want the data to be > persistent. Wow this is really awesome. This is exactly what I need. Thank you. > >> IMHO this is a pure bug. Please correct me if I'm wrong, I'll plan to >> fix that by allocation separate context for each dev. > > I don't have a problem with allowing it as an option as long as the > original behavior can be preserved. But again, I think target mode is a > better bet if you actually care about what's being stored on the > "media".
> > -- > Martin K. Petersen Oracle Linux Engineering
