Tom Horsley wrote:
I just realized that sometime fairly recently my usb2
drive I use for backups has stopped showing up as
/dev/sdc and instead shows up as /dev/sdd (with no
device named /dev/sdc anywhere).
Wah happened?
How can I reliably mount my backup drive on /backup
if the device name changes at random?
Hopefully my fixed disks will at least stay sda
and sdb?
A bit of udev rules tweaking will cure this. A udev rules editor is in
the works, as I understand things, but for now its just a little grunt
work. The rules will apply going forward, so just copy the new rules
file to an upgraded or new system and you are good to go.
make sure you have usbutils installed -- it is not by default.
# yum install usbutils
# lsusb
The goal with lsusb is to identify the vendor and device numbers for
your drive.
Some external enclosures have their own UDB hub, so they show up twice.
My WD does:
-> sudo lsusb
Password:
Bus 003 Device 002: ID 050d:0109 Belkin Components F5U109/F5U409 PDA Adapter
Bus 003 Device 001: ID 0000:0000
Bus 001 Device 001: ID 0000:0000
Bus 004 Device 001: ID 0000:0000
Bus 004 Device 002: ID 046d:c03f Logitech, Inc.
Bus 005 Device 001: ID 0000:0000
Bus 005 Device 003: ID 1058:0500 Western Digital Technologies, Inc.
Bus 005 Device 005: ID 1058:0404 Western Digital Technologies, Inc.
Bus 005 Device 002: ID 413c:a005 Dell Computer Corp.
Bus 002 Device 001: ID 0000:0000
What I need are the values for the disk. In my case its either
1058:0500 or 1058:0404.
To tell, I have to do a lsusb -v
That gives me WAY more info than I want, but run it to a temp file. I
know what I am looking for, because I have the numbers.
# lsusb -v > /tmp/moo
# vi /tmp/moo
search for those two numbers. One will say hub (or nothing), and one
will say disk (look for iProduct a few lines after the number).
Ok, so now I have the number that lsusb gave me.
# vi /etc/udev/rules.d/65-local.rules
add:
# Western Digital 320GB External
SYSFS{idVendor}=="1058", SYSFS{idProduct}=="0404", SYMLINK+="big%n"
Now whenever the drive is connected a link is made to /dev/big(n)
Now edit /etc/fstab:
/dev/big1 /data1 ext3 defaults 0 0
Alternatively, use the automounter so that the system doesn't complain
coming up if the drive is not there.
add a line to /etc/auto.master:
/- /etc/auto.big
then create /etc/auto.big
# External USB
/data1 -fstype=ext3 :/dev/big1
Restart the automounter:
# service autofs restart
hal may mount it a second time, but hey, its mounted where I want it AND
where hal wants it. :)
All done.
Of course 'big' and 'data' are arbitrary :)
I believe that this will be the 'correct' method going forward. A tool
will scan your USB devices, and create the rules file for you. For now,
its a 5 minute job.
Good luck!
