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.
It just means that there are two reasons for not removing that kernel. But once another new kernel is added, then those will refer to different kernels.