Bug#387780: initramfs-tools: power cut during update-initramfs leaves system unbootable

[maximilian attems <maks@sternwelten.at>]

On Wed, Sep 20, 2006 at 10:17:12AM +0200, Sven Luther wrote:
> On Wed, Sep 20, 2006 at 09:23:15AM +0200, Thiemo Nagel wrote:
> > >>A power cut during update-initramfs may leave the system in an unbootable 
> > >>state as the old initrd.img is overwritten, but the new initrd.img is not 
> > >>yet completed.  (This happened to me when my laptop battery ran empty.)  
> > >>A simple fix would be to create the new initrd.img as a temporary file 
> > >>and move it to replace the old initrd.img only after image creation has 
> > >>been finished.  That way, the chance to have an unbootable system after a 
> > >>power cut would be significantly lower, restricted to situations in which 
> > >>the old initrd.img doesn't work anymore.
> > >
> > >A better fix would be to always keep a copy of the old vmlinuz/initrd.img 
> > >pair
> > >or ramdisk including vmlinuz.
> > >
> > >This would solve lot of problems of this kind, and always keep one or more
> > >fallback to older kernels.
> > 
> > Absolutely.  That solution would require some more thought and work... 
> > ;-)  As far as I have understood update-initramfs is called on many 
> > occasions and also possibly multiple times during a single apt-get run 
> > (not only kernel upgrades but also upgrades of other packages, like e.g. 
> > mdadm), so one would have to take some care to identify and backup the 
> > last known-working kernel/initrd.img pair.
> 
> What about backuping the currently running one ? Or keeping load of backups ? 
> 
> But the idea was to ask this in a debconf question at lower priorities :
> 
>   We have detected multiple kernels installed.
>     current default is : ...
>     previous default was : ...
>     currently running kernel is : ...
>     newly installed kernel is : ...
>     list of available kernels :
>       ...

nono, not debconf please.
 
> Then the user can change either the default or backup kernels, and how many he
> would like to save and so on.
> 
> ramdisk generators, bootloaders and co should share in this scheme, and
> everything will work happily thereafter.

the idea is to backup on an update call any initramfs 
that is older than a certain time, lets say 6h or maybe 24h
thus not created while upgrading mdadm, udev, usplash, cryptsetup or
so together.

will be in 0.81 update-initramfs.

regards

-- 
maks