I understand that Hibernate works by dumping the RAM into a file in the swap and the system boots from that file, while resuming.

I wanted to know if this affects in anyway with Updates that require restart.

To be specific, if I have installed an Update which requires Restart and I just Hibernate, will it lead to any conflicts? Will the Update safely wait till I restart the next time?

It could be days before next restart and I want to be sure I can peacefully Hibernate without having to worry about breaking system components. I know that in general terms it shouldn't cause any issues, but would like to understand in a deeper and technical way.

  • 2
    Theoretically, the system resumes to the exact same state that it was in when hibernated, Thus, restart will still be required. Note: the update won't take effect until restarted. Or at least restarting the service that was updated.
    – ravery
    Nov 19, 2017 at 11:24
  • @ravery, could you explain bit further please? I did understand quite a bit from this answer askubuntu.com/a/36729/574724
    – Yaksha
    Nov 20, 2017 at 4:41

1 Answer 1


If you encounter bugs in the code implementing hibernate and resume it is possible that the system will not resume properly and may need to be power cycled in order to restart everything.

Assuming that didn't happen, what will happen is the following:

  • After resume you will be running the same kernel version as before you hibernated.
  • Most user mode software will also be running the same version as before. Even if the old version has been deleted from disk the file system driver will know about open files and keep them physically present on disk until they are no longer in use. That works while the system is running as well as across hibernation. (External storage devices can cause problems, so don't put your root file system or swap on a USB device.)

Thus hibernation will not be a substitute for rebooting if you installed an update that required a reboot to take effect.

Hibernating will restart a few services which will thus be running the latest updated install after resume. However those services could also have been restarted without hibernating.

Some services are automatically restarted when updates are installed.

Applications will generally have to be restarted by the user because it will always be at least a little bit intrusive to the user. Thus you will for example see browsers inform the user that a restart is needed, but the user still decides when it needs to happen.


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