lvm snapshot for menuconfig of old and new kernel [solved]

[duxsco]

Hi.
I would like to know whether I can do the following:

Chroot into snapshot and open menuconfig of old kernel:


Code:

dasa ~ # lvs   LV        VG   Attr     LSize   Pool Origin Data%  Move Log Copy%  Convert   root      dasa owi-aos- 200,00g dasa ~ # lvcreate -l100%FREE -s -n root_snap /dev/dasa/root dasa ~ # mount /dev/dasa/root_snap /mnt/snap dasa ~ # rsync -av /boot/ /mnt/snap/boot/ dasa ~ # mount -t proc none /mnt/snap/proc dasa ~ # mount --rbind /sys /mnt/snap/sys dasa ~ # mount --rbind /dev /mnt/snap/dev dasa ~ # chroot /mnt/snap /bin/bash dasa ~ # source /etc/profile dasa ~ # export PS1="(chroot) $PS1" (chroot) dasa ~ # eselect kernel list Available kernel symlink targets:   [1]   linux-3.4.41-gentoo * (chroot) dasa ~ # genkernel --menuconfig --save-config --lvm all

Emerge new kernel outside the snapshot and open menuconfig of new kernel in a different terminal window:


Code:

dasa ~ # emerge -avuDN world dasa ~ # eselect kernel list Available kernel symlink targets:   [1]   linux-3.4.41-gentoo *   [2]   linux-3.8.8-gentoo dasa ~ # eselect kernel set 2 dasa ~ # genkernel --menuconfig --save-config --lvm all

That way I have the config of the old and new kernel side by side.

[linear]

Greetings,

Well, if I understand what you are trying to do, you want to grab a copy the file kernel-config-<arch>-<kernel version>-<kernel local version> from the old kernel (READ: inside the snapshot) and compare that with the one from your current kernel?

The key to what you are trying to do is finding out where genkernel saves it's kernel config files by default; under /etc/kernels/.

Once you have a copy of each of the kernel configs on your system, you can just do:

[duxsco]

Hi linear. Thanks for the quick response.
I think it's easier to compare two kernels by looking at their configs with menuconfig than running "diff /etc/kernels/kernel-config-x86_64-3.8.8 /etc/kernels/kernel-config-x86_64-3.4.41".
If you just upgraded to a new kernel you just have the standard kernel config which differs from the old and well-configured kernel in hundreds of lines. I would like to know whether s.th. speaks against mounting proc, sys and dev in the mounted snapshot folder and running two instances of menuconfig at the same time.
Will this mess up proc, sys or dev?

[linear]

Hmmm...

Well, while the configs are much easier to read with menuconfig, it will take a LOT of flipping between terminal windows and pages within 'make menuconfig' to find all the differences, and the probability of missing something is pretty high. If you are using a standard terminal (e.g. 80 characters wide), then how about trying something like this:

[Hu]

[duxsco]

Thanks. I forgot that this is possible:

Terminal 1:

Code:

# cd /usr/src/linux-3.4.41-gentoo # make menuconfig

Terminal 2:

Code:

# cd /usr/src/linux-3.8.8-gentoo # make menuconfig

So, lvm isn't needed. Problem solved . I'll use menuconfig or diff depending on the situation. Thanks for the help.