[ale] flash ddrives (2)

Brian Pitts bpitts at learnlink.emory.edu
Thu Dec 14 11:35:57 EST 2006


Instead of mounting by physical location, you could specify the UUID or 
label. Find them with

ls /dev/disk/by-label -lah

ls /dev/disk/by-uuid -lah

You need to reformat or use mtools to specify the label on a FAT device. 
e2label can do it for ext2/3.

In your fstab you would specify LABEL=<label> or UUID=<uuid> instead of 
/dev/<DEVICENODE>.

Or you could use udev to specify a persistent device node for each 
device based on a unique attribute.

First find a device's attributes with udevinfo -a -p `udevinfo -q path 
-n /dev/<DEVICENODE>`

Then find one that's unique. For example, with my USB key at 
/devices/pci0000:00/0000:00:02.2/usb3/3-3 I find the value 
SYSFS{serial}=="6E530B001BE7"

Now you'd want to create a file with this rule in /etc/udev/rules.d/ . 
The numbers in the file names are treated similarly to the those in 
/etc/init.d; lower means sooner. For example

vim /etc/udev/rules.d/10-mystorage.rules

Now You could add a rule, in my case I might add

SYSFS{serial}=="6E530B001BE7", KERNEL=="sd?1", NAME="usbkey"

This would say that if a device with that serial is the first partition 
anywhere on the scsci bus create a device node for it at /dev/usbkey.

Now restart udev with /etc/init.d/udev restart

and edit your fstab to refer to the new device node.

I hope that's helpful.

-Brian



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