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Autor: Hendrik Boom
Data:  
Para: Didier Kryn
CC: dng
Assunto: Re: [DNG] Trouble getting copied system to boot
On Sun, Dec 17, 2017 at 12:37:03PM +0100, Didier Kryn wrote:
> Le 16/12/2017 à 23:55, Hendrik Boom a écrit :
> >I m copying my entire Devuan system to new partitions on the same computer. but I can't get the copy system to boot.
> >
> >I plan to upgrade the copy to ascii, keeping the old system in dual-boot scenario just in case I'm not expecting problems, but I've had them on Debian upgrades years ago, and they sometimes arise from causes that have nothing to do with the quality of the old and new systems.
> >
> >The messge I get is:
> >
> >vmlinuz-3.16.0-4-686-pae not found
> >you need to load the kernel first
> >
> >But vmlinuz-3.16.0-4-686-pae *is* the kernel. I don't know how to load the ernel before it can find the kernel.
> >
> >***
> >
> >Here's how I got to this point.
> >
> >/boot and /ascii/boot (I'll use the names these partitions have on the old system) are partitions of their own on a DOS-style partitioned disk, as is swap.
> >
> >/dev/sda6 on /boot type ext4 (rw,relatime,data=ordered)
> >/dev/sda7 on /ascii/boot type ext4 (rw,relatime,data=ordered
> >
> >oot@notlookedfor:/home/hendrik# swapon
> >NAME      TYPE      SIZE USED PRIO
> >/dev/sda5 partition 4.7G   0B   -1
> >root@notlookedfor:/home/hendrik#

> >
> >The other partitions are within LVM.
> >
> >/dev/mapper/jessie-devuan--home on /home type ext4 (rw,relatime,data=ordered)
> >/dev/mapper/jessie-tmp on /tmp type ext4 (rw,relatime,data=ordered)
> >/dev/sda6 on /boot type ext4 (rw,relatime,data=ordered)
> >/dev/mapper/jessie-devuan--usr on /usr type ext4 (rw,relatime,data=ordered)
> >/dev/mapper/jessie-devuan--var on /var type ext4 (rw,relatime,data=ordered)
> >/dev/sda7 on /ascii/boot type ext4 (rw,relatime,data=ordered)
> >/dev/mapper/jessie-ascii--root on /ascii/root type ext4 (rw,relatime,errors=remount-ro,data=ordered)
> >/dev/mapper/jessie-ascii--usr on /ascii/usr type ext4 (rw,relatime,data=ordered)
> >/dev/mapper/jessie-ascii--var on /ascii/var type ext4 (rw,relatime,data=ordered)
> >
> >The partitions with devuan in their mapper names belong to the jessie system;
> >those with ascii in theor names are intended for the future ascii system, and currently are a copy of the ones for jessie, exceot of course that /jessie/root/etc/fstab (ascii's fstab) hace had the partition names swapped around, so that for example /boot there is ascii's /boot instead of jessie's, and the old systems partitions are known as /jessie/boot, etc.
> >
> >Just before today's tests, I used rsync to synchronise the two systems, and then copied the modufied fstab to the ascii system, just to make sure it was the new one instead of the rsync'd one.
> >
> >Then reboot. It offered me a choice of systems to boot; I chose the new one, and got the error message I presented above.
> >
> >vmlinuz-3.16.0-4-686-pae not found
> >you need to load the kernel first
> >
> >So ... where do I start to look for the problem. How far along in the boot process is the system component that produces the above message? Are there any usable diagnostic tools at this point in the boot process?
> >
> >Yes, that file *is* present in /ascii/boot.
> >
> >root@notlookedfor:/home/hendrik# ls /ascii/boot
> >config-3.16.0-4-686-pae      lost+found
> >grub                 System.map-3.16.0-4-686-pae
> >initrd.img-3.16.0-4-686-pae  vmlinuz-3.16.0-4-686-pae
> >root@notlookedfor:/home/hendrik#

>
>     I guess your two root partitions must have different uuids and Grub must
> know it to choose.
>
>     Thats the problem of specifying boot partition by uuid. I like using
> uuids in fstab to keep each OS consistent, but for the root partition passed
> to Grub, I personnaly think device name is just more convenient. I guess
> this consideration doesn't solve your problem though :-(
>
>     Check also the uuids in your new fstab is fine and won't mix with the
> other OS.


Both OS's mount the same partitions, with the same UUIDs. Only the
mount points are different.

I makes it easier to compare them.

-- hendrik