When it comes to power options in Linux distros, there are Logout, Shutdown, Suspend, and Hibernate functions. Logout and Shutdown are self-explanatory. Let’s learn what are Hibernate and Suspend operations, and differences between them.
Suspend is same as Sleep in Microsoft Windows. This mode doesn’t power off your computer. RAM is still powered during the entire suspend state, and so the machine will still be consuming power all the time. This mode is not an efficient choice for laptops as the battery will get drained.
However, it may serve as an excellent option to keep the working session intact along with programs and apps that you were using. Later when you resume the PC after wake-up from suspend, you will have the session ready.
Due to this nature of the Suspend mode, you have to be careful that the computer never loses power or runs out of battery life as the session and files will not be saved, and data-loss is imminent for the unsaved data.
In the Hibernate mode, the computer shuts down the computer entirely, and hence so there will be no power consumption what-so-ever when the PC is in the Hibernation state.
When you put the computer to Hibernate, the session content from the RAM are moved to hard disk swap space, and after that, the system is powered off.
When waked up from Hibernation, the session contents from swap gets copied back to RAM, and so it takes more time than sleep to get the PC into working state.
Why don’t some Linux distros have Hibernate enabled by default?
Hibernate is not a smooth going feature at times due to the very nature of how it works and how the hardware must support it. If the SWAP partition is not set correctly, there could be data loss due to crash, and computer freeze at startup are common problems associated with Hibernation.
Typically, Linux needs the size of RAM for its SWAP size, but not everybody follows this in its entity, leading to the Hibernate problems. Ubuntu had Hibernate as a default feature in the Power panel, but since Ubuntu 12.04 LTS, the feature was dropped due to ever increasing problems reported by several users.
But it doesn’t mean your PC can’t hibernate anymore. All you need to do is first check if your computer hardware is compatible with the mode.
How to check if your PC is compatible with Hibernate?
Before proceeding further, make sure to save all the unsaved documents in the session.
Launch ‘Terminal’ and type the following command:
Your PC will turn off. Turn ON the computer and check if the session you had before you entered the pm-hibernate command is intact or whether you logged into an empty desktop.
If your session is lost, it implies your PC will not hibernate. Check if your swap partition is at least as large as your available RAM. Linux recommends twice as the size of RAM for its SWAP partition. For example, if your PC has 8 GB of RAM, then you should be having at least 16 GB of SWAP partition.