I recently rearranged my partitions on my disk to move my /home to a separate partition and to create a media storage volume. That makes my partition layout look like this:
Old New
sda1 /boot sda1 /boot
sda2 / sda2 /
sda3 /mnt/backup sda3 /home
sda4 (swap) sda4 (extended)
sda5 /mnt/extra
sda6 (swap)
(The backup partition was moved to a separate physical device.)
When I did this, my hibernate suddenly stopped working:
# echo disk > /sys/power/state