[gentoo-user] UDEV rule problem

[gentoo-user] UDEV rule problem

[Helmut Jarausch]

Hi,

I have two external USB3 hard disk enclosures. They have the same  
vendor, model and the same serial number (unfortunately).
Vendor, model and serial occur in the usb-subsystem only.

Since the hard drives within theses enclosures have different  
capacities, there is a different ATTR{size} value in the  
block-subsystem.
But this doesn't have any vendor info.

How can I write to different udev rules to distinguish these two  
external hard disks?

Many thanks for a hint,
Helmut

Re: [gentoo-user] UDEV rule problem

[Stefan G. Weichinger]

Am 2016-11-14 um 15:31 schrieb Helmut Jarausch:
> Hi,
>
> I have two external USB3 hard disk enclosures. They have the same 
> vendor, model and the same serial number (unfortunately).
> Vendor, model and serial occur in the usb-subsystem only.
>
> Since the hard drives within theses enclosures have different 
> capacities, there is a different ATTR{size} value in the block-subsystem.
> But this doesn't have any vendor info.
>
> How can I write to different udev rules to distinguish these two 
> external hard disks? 

It's not udev, but why not use the UUIDs of the filesystems?

# ls -l /dev/disk/by-uuid

and then for example in /etc/fstab

UUID=028da5ef-4e73-405a-b739-d59204c54921 /mnt/externaldisk1 ext4 
relatime,noauto,user 0 1
UUID=fae458a3-da30-43c5-81f1-be2d49215b09 /mnt/externaldisk2 ext4 
relatime,noauto,user 0 1

just a suggestion, I don't know your specific use-case

[gentoo-user] Re: UDEV rule problem

[Kai Krakow]

Am Mon, 14 Nov 2016 15:31:58 +0100
schrieb Helmut Jarausch <jarausch@skynet.be>:

> Hi,
> 
> I have two external USB3 hard disk enclosures. They have the same  
> vendor, model and the same serial number (unfortunately).
> Vendor, model and serial occur in the usb-subsystem only.
> 
> Since the hard drives within theses enclosures have different  
> capacities, there is a different ATTR{size} value in the  
> block-subsystem.
> But this doesn't have any vendor info.
> 
> How can I write to different udev rules to distinguish these two  
> external hard disks?

I've seen many drives where really the serial number as reported by
Linux is the model number, and the serial number is somehow invisible...
Not sure if this is a kernel bug or some ATA protocol violation.
Especially USB enclosures are a problem with this...

-- 
Regards,
Kai

Replies to list-only preferred.

[gentoo-user] Re: UDEV rule problem

[Martin Vaeth]

Helmut Jarausch <jarausch@skynet.be> wrote:
>
> Since the hard drives within theses enclosures have different
> capacities, there is a different ATTR{size} value in the
> block-subsystem.
>
> How can I write to different udev rules to distinguish these two
> external hard disks?

KERNEL=="sd[a-z]*", ATTR{size}=="31...", ATTRS{model}=="...", SYMLINK+="d1%n", OPTIONS="last_rule"