On Tue, Apr 28, 2009 at 1:20 PM, Milos Muzik <[email protected]> wrote: > > Andrey Kuzmin wrote: >> IIRC (it's over a years since I last looked at user-space iSCSI target >> code), iscsit supports pass-through mode so that running local tape >> target should not be a problem. Of course, whether such a mode was >> envisaged/designed for is a totally different question. >> >> Regards, >> Andrey >> > > The problem is that iscsitgtd sends SCSI commands to the backing device on its > own in raw mode during initialization phase. This is an excerpt from iscsitadm > man page: > > ......... raw indicates > that the emulator will use the uSCSI interface and pass > the command blocks directly to and from the device. The > use of raw also implies the option --backing-store will > be entered. The argument to this option is the full > pathname to the device node normally found in /dev. If > you use --backing-store, the size of the store is deter- > mined by a SCSI READ_CAPACITY command or, if the backing > store is a regular file, by stat(2). > > The consequence of the text above is that tape device can't be used as a > backing > store even in raw mode. The READ_CAPACITY which is always sent to the device > is > a block device specific command and fails with sense key 0x5 (Illegal Request) > when sent to a tape. > > It seems that the iscsitgtd was not designed for tape backing at all. >
Right, though I'm unclear on why iscsitgtd starts with READ_CAPACITY instead of passing through target discovery commands. Anyway, driving tape target apparently was not envisaged. Regards, Andrey > Regards, > Milos > _______________________________________________ storage-discuss mailing list [email protected] http://mail.opensolaris.org/mailman/listinfo/storage-discuss
