[TriLUG] How was your week?

Rick DeNatale rick.denatale at gmail.com
Wed Aug 9 18:15:33 EDT 2006

On 8/9/06, Tanner Lovelace <clubjuggler at gmail.com> wrote:
> On 8/7/06, Rick DeNatale <rick.denatale at gmail.com> wrote:
> > Well, this week isn't starting too well.
> >
> > Yesterday, I decided to upgrade the home server from Ubuntu breezy  to dapper.
> >

> Can't you just select an older kernel from the grub menu?
> If you did "apt-get dist-upgrade" the older kernels should
> still be there.  (I assume that's what you did, since you're
> only downloading the install disk after the fact.)

Yeah, that was my first thought.  But IIRC, the old kernels wouldn't
load either.

The problem was that the initramfs didn't have the modules needed to
mount the root file system, which is in an LV on a raid1 array.

In general terms, the fix was to boot using the install disk, then
escape out to a shell, do a few modprobes to get the LVM and raid
support, mount my root file system, and then chroot to it, and then
re-install the kernel.

It was a bit more complicated than this because this machine has /boot
in a separate partition, and that that partition is on one of the two
9GB SCSI drives which also hold that LV.  So I had to figure out how
to get /boot updated, since once I'd chrooted, I couldn't see
/dev/sda1 or /dev/sdb1 anymore.  The solution was to make a directory
on the / LV and copy the /boot filesystem there,  then copy it back
after I exited from chroot.

Then the last boot problem, I hope, was that I've actually got a
backup of the /boot partition on the OTHER scsi drive, and that my
fstab was mounting /boot from the drive which the BIOS wasn't booting
from.  I only discovered that when I had successfully booted,
installed a 686 kernel and couldn't find IT when I tried to re-boot.

Now I'm down to a few apps which need to be reconfigured to work.

So, I've learned more than I wanted to about how Ubuntu builds init
ramdisks, and how hard it is to do system upgrades when you only have
one system to work with.   I guess that's one of the reasons virtual
systems are getting so much play these days.
Rick DeNatale

IPMS/USA Region 12 Coordinator

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