Re: optional delay after partition detection at boot time

[Willy Tarreau <willy@w.ods.org>]

On Sun, Jun 12, 2005 at 07:22:45PM -0700, David Lang wrote:
> On Sun, 12 Jun 2005, Willy Tarreau wrote:
> 
> > - you don't know the root device, so the kernel will
> >   panic at boot because it cannot find the root device.
> >   In this case, you have the partition list still on
> >   the screen as it's among the latest things in the
> >   boot order. And if your kernel reboots upon panic,
> >   just boot it with panic=30 so get 30 seconds to read
> >   the partition table.
> 
> I have one machine inmy lab that turns out to need to boot from /dev/sdq1
> 
> trust me, that partition info has LONG since scrolled off the screen by 
> the time it fails to mount and panics.

Interesting. How many total partitions do you have ? I ask this because
David Alan Gilbert proposed a patch to dump the partition list on the
screen upon panic. Perhaps it's larger than the screen in you case ? If
you have more than 25 partitions, to you think they can fit with 2 or 3
columns ?

> I ended up setting up a serial console to capture the boot to figure this 
> machine out, but that's a pretty extreme measure to have to go to.
> 
> David Lang
> 
> P.S. I had to do this after grub failed to mount by label (my guess is 
> that grub only looks at so many drives before giving up on finding the 
> label) so don't tell me that I should just use labels and then I wouldn't 
> have to worry about this type of thing

I wouldn't tell you that, I *hate* labels. It causes lots of problems
when you simply move some disks between machines.

Regards,
Willy