Hello.
After upgrading to opensuse 13.1 I have found that I have enabled the option in / etc / zypp / zypp.conf to have multiple kernels installed.
I do not remember this option manually activated, is automatically activated after upgrading?
Thank you.
This is enabled by default since 12.3.
If you haven’t changed the config file manually rpm will replace it with the new version. If you did edit it, it should not get replaced though, zypp.conf.rpmnew will be created instead with the new defaults. It would be your own job to merge that with the existing /etc/zypp.conf if necessary.
There’s also the command “rcrpmconfigcheck” to find/list those *.rpmnew and *.rpmsave files on your system.
On 2014-02-10 14:36, jony127 wrote:
> I do not remember this option manually activated, is automatically
> activated after upgrading?
Should be. it can save your life 
–
Cheers / Saludos,
Carlos E. R.
(from 13.1 x86_64 “Bottle” (Minas Tirith))
Why the multikernel is now enabled by default? Is it really necessary?
It is assumed that minor kernel updates and are tested.
Testing does not guarantee perfection. Why? Kernel updates contain fixes which may result in adverse side effects not found during testing. Also, human beings sometimes make mistakes. Without a system backup, a re-install might be the only recovery in some situations.
If a problem results, multiple kernels give the user a simple way back to reboot the previous kernel. I don’t recall anyone complaining before. 
On 2014-02-11 15:16, jony127 wrote:
>
> Why the multikernel is now enabled by default?
Because it is good. Many people requested it.
> Is it really necessary?
Yes.
> It is assumed that minor kernel updates and are tested.
Many people got their machines un-bootable after one of those “minor”
kernel updates.
If you are sure that you are safe, just disable the feature. But then do
not complain if your machine does not boot after a kernel update one day…
–
Cheers / Saludos,
Carlos E. R.
(from 13.1 x86_64 “Bottle” (Minas Tirith))
I guess another advantage of multiple kernels is that the running kernel’s modules stay on the hard disk.
In earlier versions (12.2 and before) you (mostly) had to reboot immediately after installing a kernel update, because installing the update removed the currently running kernel’s modules. So without rebooting, the kernel couldn’t load any modules from the hard disk anymore.
The effect of this was, that you suddenly could not access any USB sticks/external hard disks you connected f.e.
With multiple kernels this problem doesn’t exist because the current kernel modules don’t get deleted anymore.
jony127 wrote:
openSUSE 13.1(Linux 3.11.6-4-desktop x86_64|
Intel(R) Quad Core™ i5-4440 CPU @ 3.10GHz|8GB DDR3|
GeForce 8400GS (NVIDIA-Linux-x86_64-331.38)|KDE 4.12.2
ok I understand the advantage but a problem, when the kernel is updated the previous entries did not appear in the grub, only the new update. So I can not boot previous kernel versions.
Look in advanced in the boot screen
On 2014-02-11 17:56, wolfi323 wrote:
> I guess another advantage of multiple kernels is that the running
> kernel’s modules stay on the hard disk.
That’s an interesting point… it did not occur to me.
–
Cheers / Saludos,
Carlos E. R.
(from 13.1 x86_64 “Bottle” (Minas Tirith))