From: "Michel Salim" <michel salim gmail com>
>In Rawhide, USB external drives are not detected if they are plugged
>in at boot time, requiring power-cycling before the required device
>nodes are created in /dev and gnome-volume-manager works.
>
>Has there been any changes in the boot process that might have caused this?
This problem has been around since August 2006. See
https://bugzilla.redhat.com/bugzilla/show_bug.cgi?id=204396 for the details.
The short version is it works for a little while then it stops working due
to some update. It works again, stops working. repeat. There is no rhyme or
reason to it.