[PATCH] mkinitrd rescue mode

[Peter Jones]

On Mon, 2005-06-06 at 16:59 -0400, Bill Rugolsky Jr. wrote:
> On Mon, Jun 06, 2005 at 03:31:42PM -0400, Peter Jones wrote:
> > > It would also give people the ability to try to rescue corrupted root
> > > filesystems without needing special infrastructure (like a PXE server) 
> > > and without having to physically be near the machine (with a CD boot).
> > 
> > This is a strawman -- your scenario is that they've just installed or
> > upgraded, in which case they've already set up this infrastructure or
> > are already close to the box.
> 
> I don't understand why you think that everyone should be running a PXE
> server, which can be a security nightmare as well as an administrative
> hassle.

I don't think that at all.  In the scenario we were discussing, the
system had just been installed or upgraded.  In that case, I'm 100% sure
you have things set up to boot either a CD, a PXE image, or some other
boot media that you can just as easily put the rescue image on.

> The following is a real-world, though perhaps ill-advised, configuration:
> 
>  o /boot on RAID1 across several /dev/sd?1
>  o  swap on RAID1 across several other /dev/sd?1
>  o Everything else on LVM2-over-RAID5 on /dev/sd?2
> 
> [As disks have gotten larger and cheaper, putting the root file system on
>  RAID5 has become less attractive, but people still do it.]
> 
> A disk failure followed by a crash/outage requires manual intervention to
> bring the RAID5 back online, since we do not have RAID5 journaling yet,
> and it is still early days for RAID6.  Getting to a command prompt and
> running mdadm to reassemble the array would certainly be quite useful.

In this scenario you're replacing a drive.  I hope you've got physical
access to the machine.

Also, this isn't a very good example -- your random drive failure is
relatively likely to wedge the bus, etc.  In that case, this is the
exact same scenario as if /boot isn't available at all.

You have to go and touch the box here.  If you have to touch the box,
then I don't buy "I couldn't boot a CD".
-- 
        Peter