sudo systemctl hibernate

on Centos, I was trying to hibernate my machine:

sudo systemctl hibernate

A dependency job for hibernate.target failed. See 'journalctl -xe' for details.

journalctl -xe


Failed to write mode to /sys/power/disk: Operation not permitted

https://ask.fedoraproject.org/en/question/41118/f20-unable-to-hibernate-syspowerdisk-disabled/


I removed "safe boot" option in the BIOS settings, and now I am able to hibernate! Amazing!


See also this https://www.thegeekdiary.com/centos-rhel-7-shutting-down-suspending-or-rebooting-commands-systemctl/, maybe "suspend" is cheaper safer and faster than hibernate...