Today I experienced a system hang after updating to latest openSUSE kernel and I am looking for a way to secure myself against similar issues in future by increasing the number of previous kernel versions.
I have found this and this info and checked how it is on my system:
I also had a hang on a KVM virtual machine – reported as Bug 1104121.
grep multiversion.kernels /etc/zypp/zypp.conf
multiversion.kernels = latest,latest-1,running
What I did, was immediately add “oldest” (before “latest”). That way, I will keep a known good kernel. At some time in the future, I’ll remove that “oldest” and that kernel will be uninstalled at the next kernel update. But I’ll wait until I know I have a good kernel before I do that.
No need to do anything in regards to bootloader or anything else?
No, you should not have to touch bootloader. But you will have to select a good kernel from the boot menu. Or you could uninstall the bad kernel, and then it will default to booting the good one.