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

[Canek Peláez Valdés]

On Wed, Aug 1, 2012 at 6:59 PM, Canek Peláez Valdés <caneko@×××××.com> wrote:
> On Wed, Aug 1, 2012 at 6:34 PM, Alex Schuster <wonko@×××××××××.org> wrote:
>> Hi there!
>>
>> I do not understand the numbering of my hard drives. There may be some
>> inherent logic, but whenever I make some changes, like replacing drives,
>> or changing BIOS settings, the order changes. Maybe it's even more random.
>>
>> 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?
>
> If you want to distinguish partitions, I would recommend using labels
> (in fstab too); those never change unless you specifically change
> them. Then, no matter how you put them in your machine, they will get
> mounted correctly, and then you don't need to fuzz with udev rules.
> Also, as a superficial bonus, they get mounted using the label and it
> looks nice in your file browser.
>
> The drives themselves I see no reason to recognize them, why do you
> need to do that?

Oh, and I forgot; doesn't the links in /dev/disk/by-id,
/dev/disk/by-label, /dev/disk/by-uuid do what you want to?

Regards.
-- 
Canek Peláez Valdés
Posgrado en Ciencia e Ingeniería de la Computación
Universidad Nacional Autónoma de México