Error logged on host during hibernate:
(XXXXXX is a 6 digit number)Image allocation is XXXXXX pages short
This sounds like the swapspace (where hibernate data should be saved) is running out of space, but the problem occurres even if there is 30GB of free swap space and only 2GB of ram used.
While the vm is running, the host can hibernate. After a VM shutdown, the host can hibernate. But after a VM set to save state, hibernation of the host fails. Even hours after saving the state of a VM, the host cannot hibernate.
Steps to reproduce:
Boot host
start some programs (i.e. firefox, terminal, qualculator, ...)
start vbox
boot a vm
save the state of the vm
Use the computer for a while (browse some websites, play with the calculator,....)
Hibernate the host - it will fail and show lock screen
Unlock the computer
run "free -h" in terminal to check that there is lots of space available on swap partition to store all ram content
Try hibernate again - it will fail and show lock screen
Unlock the computer
Close ANY program (i.e. qualculator)
Try Hibernate again - success.
Saving the state of a VM causes the hibernate to be blocked. Closing ANY program after saving the state of a VM unblocks hibernate.
I'm using XFCE.