On Mon, Aug 28, 2006 at 12:19:42AM +1000, Luke Kendall wrote:
> Three questions:
>
> 1) Do you install Ubuntu so that you can choose raid, by installing from
> the Alternate CD?
I only ever use the alternate/server CD, and I do that all the time, so I
presume that the answer you want is 'yes'.
> 2) Has anyone here got a Grub system booting from a raid1 / (slash) root
Hell yes.
> 3) Can you tell Ubuntu to use Lilo instead of Grub as the boot loader?
Yes, you can, but I can't imagine a single reason on the planet why you
would want to. Grub takes a bit of learning, but actually having a flexible
and semi-sensible boot loader is more than enough reward.
> I do think though that for grub and raid (unlike lilo and raid), the
> best you can do is double up the stanza for each kernel you want to
> boot and manually choose the working drive when a drive in the raid
> mirror fails?
Depends. If you're using PATA, which has explicit device names depending on
where you plugged the drive in, then yes, but I can't imagine how you'd get
around that. For SCSI or SATA, which tend to just allocate starting from
'a', you should be OK with identical configration and dual-installing grub.
> I've been trying to retrofit raid mirroring on a system after installing
> Ubuntu 6.
That would be 6.06LTS, yes?
> I thought the data might be lost, but by booting up as far as I can
> from the semi-hosed system, I can at least see the slash filesystem and
> mount other areas, and copy everything off. (Interesting to see a
> handful of errors in the copy, that match what fsck reported as
> problems.)
Probably where the RAID superblock scribbled on some data.
> I'm thinking I should install Ubuntu again from scratch, and redo the
> 10GB of extra package installation and all the configuration for mail
> etc. again. :-(
10GB of packages? Holy moley that's a lot of software.
> I gather I do this by installing from the Alternate CD, which is less
> beautiful but gives you more control over the installation?
Ayup. Also put LVM in there while you're at it. You'll thank me sooner or
later. <grin>
> Is there a way to note the list of all the packages I installed, so I
> can avoid spending another 4 hours selecting the packages again?
On the old system:
dpkg --get-selections > /tmp/package-list
Copy /tmp/package-list to somewhere safe, then when you're ready to go
again, copy it onto the new system and run:
dpkg --set-selections < /tmp/package-list
> A bit of google searching on ubuntu and raid strongly suggests that
> grub just doesn't work properly with a mirrored boot and/or root.
Google is lying. It works brilliantly.
> (1: Failed drives cause devices to change name.
That's a "failure" of the device naming system, but it shouldn't matter
because md scans disks to find chunks of RAID to stitch together.
> 2: Even after installing
> grub to both devices in the mirror, you still have to have double
> stanzas in menu.lst for each raw device so you *manually* choose to
> boot off the other device in the event of failure.)
I can't imagine why you'd need that, except in the above-mentioned scenario.
> I gather that in contrast, lilo stores the actual locations for the
> kernel images on both devices and *also* knows to try each device in
> event of failure.
I seriously doubt that LILO has that much smarts. My guess is that it works
because LILO just goes "blocks [list] on the first disk has my kernel".
> Can you choose to use Lilo with Ubuntu?
Yes.
- Matt
--
"We are peaking sexually when they are peaking. And two peaks makes a hell
of a good mount."
-- SMH
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