On Tue, Mar 06, 2007 at 04:09:42PM -0500, FL wrote:
> On 2/22/07, Stefan G. Weichinger <sgw AT amanda DOT org> wrote:
> >
> After watching the trouble recur, I see that the device associated with the
> changer SCSI device ID moved: it was /dev/sg2, today it is /dev/sg1. No
> changes were made to the Exabyte LTO-2 tape library  or to the SCSI card (or
> anything else). So there is something I'm failing to understand about udev,
> SCSI or the Exabyte.
> 
> Perhaps during bootup I should attempt
> 
> mtx -f /dev/sg0 status
> mtx -f /dev/sg1 status
> 
> until I have a valid status, and link
> /dev/changer to that, then refer to /dev/changer in amanda.conf. That's a
> workaround: somehow the device assigned to the changer moves on occasion,
> after a reboot. Perhaps I should be referring to the changer device in some
> other way (bus number, SCSI ID, lun...).

Does your system have sg_scan?  My FC4 does.  It would be a way of
enumerating your devices and possibly setting up udev rules to
create persistent names for the devices.

Here is a sample output on my system with a DDS3 drive + changer
id 5, lun 0+1, an LTO drive, and two usb disks.

[root@bigcow /]# sg_scan -i
/dev/sg0: scsi0 channel=0 id=5 lun=0
    HP        C1557A            U610 [rmb=1 cmdq=0 pqual=0 pdev=0x1]
/dev/sg1: scsi0 channel=0 id=5 lun=1
    HP        C1557A            U610 [rmb=1 cmdq=0 pqual=0 pdev=0x8]
/dev/sg2: scsi1 channel=0 id=4 lun=0
    HP        Ultrium 1-SCSI    E21V [rmb=1 cmdq=0 pqual=0 pdev=0x1]
/dev/sg3: scsi3 channel=0 id=0 lun=0 [em]
    ST330083  1A                3.03 [rmb=0 cmdq=0 pqual=0 pdev=0x0]
/dev/sg4: scsi4 channel=0 id=0 lun=0 [em]
    ST330063  1A                3.04 [rmb=0 cmdq=0 pqual=0 pdev=0x0]

-- 
Jon H. LaBadie                  jon AT jgcomp DOT com
 JG Computing
 4455 Province Line Road        (609) 252-0159
 Princeton, NJ  08540-4322      (609) 683-7220 (fax)