Re: [gentoo-user] Udev rules for identical hard drives

[Walter Dnes]

On Thu, Aug 02, 2012 at 01:34:04AM +0200, Alex Schuster wrote

> So I made some udev rules like this, and my drives are called /dev/hd1,
> hd2 and hd3:
>
> SUBSYSTEMS=="scsi", KERNEL=="sd?", ATTRS{model}=="SAMSUNG HD154UI",
> SYMLINK="hd1"
>
> This works fine, and this way I can address them in scripts, smartd and
> hdparm config files and such. But now I have two identical drives. I had
> this before with the drive above, but while being identical models, the
> two drives differed a little in size, so I just had to add ATTR{size}.
> This does not help with my current drives, and I find nothing
> in /sys/block/sd?/device/ that differs. Could there be another way to
> distinguish the drives, like looking at the partition scheme or something?

  You can get the ATTRS{serial} (i.e. serial number).  See the printer
example at http://www.reactivated.net/writing_udev_rules.html and adapt
to your hard drive.  Serial numbers should be unique, even amongst
otherwise identical drives...

======================================================================
I power on my printer, and it is assigned device node /dev/lp0. Not
satisfied with such a bland name, I decide to use udevinfo to aid me in
writing a rule which will provide an alternative name:

    # udevinfo -a -p $(udevinfo -q path -n /dev/lp0)
      looking at device '/class/usb/lp0':
        KERNEL=="lp0"
        SUBSYSTEM=="usb"
        DRIVER==""
        ATTR{dev}=="180:0"

      looking at parent device
'/devices/pci0000:00/0000:00:1d.0/usb1/1-1':
        SUBSYSTEMS=="usb"
        ATTRS{manufacturer}=="EPSON"
        ATTRS{product}=="USB Printer"
        ATTRS{serial}=="L72010011070626380"

My rule becomes:

    SUBSYSTEM=="usb", ATTRS{serial}=="L72010011070626380", SYMLINK+="epson_680"
======================================================================

-- 
Walter Dnes <waltdnes@××××××××.org>