Howto refresh /dev/disk/by-uuid on Ubuntu
I was recently setting up a Ubuntu server and was partitioning it after it had been installed.
There was lots of free space on the drives as the root partition was only using a small portion of the disk. After running fdisk to partition it and mkfs.ext3 on the partitions to format them I couldn't see them in /dev/disk/by-uuid.
A quick google presented the solution:
According to the man page this makes udev request the kernel device uevents, which in essence makes it read the disk info again and show it all up so you can mount it happily.