On Thu, Jun 16, 2011 at 20:15, Douglas Gilbert <dgilbert@xxxxxxxxxxxx> wrote: > On 11-06-16 02:05 PM, Kay Sievers wrote: >>> The kernel's device naming (following from how devices are >>> discovered) is topological. However at higher levels >>> the user is interested in the device identity. So if >>> unique device names were used as preferred names and >>> preferred names were unique (in a Linux system at any >>> given time) then any subsequent path to an existing device >>> would be highlighted. [That is because subsequent attempts >>> to create its preferred name would fail because it is >>> already there.] >>> >>> You don't need thousands of dollars of equipment to >>> demonstrate this point. An external single disk >>> SATA enclosure with a USB and eSATA interface will do. >> >> Udev does that already since quite a while. This is my cheap laptop: >> Â # find /dev/disk/ -name "wwn*" >> Â /dev/disk/by-id/wwn-0x50015179593f3038-part1 >> Â /dev/disk/by-id/wwn-0x50015179593f3038-part4 >> Â /dev/disk/by-id/wwn-0x50015179593f3038-part3 >> Â /dev/disk/by-id/wwn-0x50015179593f3038-part2 >> Â /dev/disk/by-id/wwn-0x50015179593f3038 > > That is my point, if that disk is eSATA and USB connected > which transport is that link pointing to? I would > prefer eSATA over USB any day but is udev that smart? Or > are we just seeing a symlink to the first (or perhaps last) > path discovered? I don't know if any bridge supports both connections at the same time. Mine doesn't. If two kernel devices fight for the same link, the last one wins, unless there are link-priorities specified in udev rules. Kay -- To unsubscribe from this list: send the line "unsubscribe linux-scsi" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
