Hey,
On Thu, Jun 10, 2010 at 11:57 PM, Ethan Baldridge
<baldridge.ethan@xxxxxxxxx> wrote:
> Thanks for the info, David, but unfortunately these are USB drives, and
> scsi_id doesn't seem to return anything (although this is with udev
> version 147, so I can try upgrading, but that patch only seems to affect
> the scsi subsystem - has something similar been done to usb?)
I think that we always use the USB serial number for any device
connected via USB. I remember something about that if the USB device
is a ATA disk and the bridge is sufficiently compatible, it should be
possible to retrieve the ATA serial number from IDENTIFY data.
Presumably it's a simple matter of attempting to run ata_id (which I
don't think we currently do).
Try checking the devices with ata_id (from udev), hdparm(8) and
skdump(1) and check if the serial reported by them is what you're
after?
(I'm mentioning skdump(1) because it has some extra secret sauce for
dealing with ATA devices behind certain kinds of USB bridges.)
> And this number actually does match what one would expect by looking at
> the bottom of the drive enclosure.
This is probably just a coincidence. In general I don't think you can
make any assumptions about what kind of serial number vendors put on
the *enclosure*. If it was ATA or SAS disks you could probably expect
the vendors to put the serial number or WWN on the hard disks itself.
That said, in the case where we can extract both the ATA serial number
and the USB serial number for a disk, I think we should prefer the ATA
one. Or maybe, for symlinks at least, we should use both. Kay, what do
you think?
David
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