Mount /usr on different partition
Yes, this is almost certainly possible.
- Mount the new partition somewhere in your filesystem.
mount /path/to/device /mnt
- Copy the contents of your current /usr to the new partition.
rsync -a /usr /mnt
- Unmount the new partition.
umount /mnt
- Update your /etc/fstab to reflect the changes.
/path/to/device /usr defaults 0 0
- Mount the new partition.
mount /usr