udev rulez!

If you're using USB drives on a Linux server, then you probably ran into the problem of mounting those drives consistently. The problem comes from the fact that the USB mounting order can change from one reboot to the next, rendering your fstab entries stale.

Fortunately, udev comes to the rescue. Just do a

ls -la /dev/disk/by-id/

and you'll find human-friendly and persistent symbolic links to the USB device nodes. For example, mine has

lrwxrwxrwx 1 root root 10 2006-09-07 08:40 usb-Maxtor_6_Y120L0_############ -> ../../sda
lrwxrwxrwx 1 root root 10 2006-09-07 08:40 usb-Maxtor_6_Y120L0_############-part1 -> ../../sda1
lrwxrwxrwx 1 root root 9 2006-09-07 08:40 usb-Maxtor_OneTouch_III_TA0071VH -> ../../sdc
lrwxrwxrwx 1 root root 10 2006-09-07 08:40 usb-Maxtor_OneTouch_III_TA0071VH-part1 -> ../../sdc1
lrwxrwxrwx 1 root root 9 2006-09-07 08:40 usb-WDC_WD16_00BB-56GUC0_############ -> ../../sdb
lrwxrwxrwx 1 root root 10 2006-09-07 08:40 usb-WDC_WD16_00BB-56GUC0_############-part1 -> ../../sdb1


These link names are guaranteed not to change because they are formed from the USB device hardware ID which itself doesn't change. Now in your fstab, instead of mounting the USB drives by referring to /dev/sdx1, you can instead refer to /dev/disk/by-id/usb-DEVICE_ID-part1.

From clear information found at Writing udev rules, by Daniel Drake.