ROOT raid (software raid 1) on UBUNTU SOLVED!

[Rich Duzenbury]

On Sun, 2004-12-05 at 16:48, Rich Duzenbury wrote:

> Are there some ubuntu specific instructions or advice?  Thanks.
> 
Well, I'll answer my own question.  See this documentation:
http://xtronics.com/reference/SATA-RAID-debian-for%202.6.html

With a few minor changes.  

There is a small section on installing wajig, I didn't bother.  'apt-get
install' works fine when needed.

I used the default installed kernel (2.6.8.1-3-386) from the ubuntu
install CD.

Don't make the mistake I did.  I though I would save myself some work
and configure disk2 at the same time as disk1.  That screws things up! 
Partition disk1, install ubuntu on sda, then partition disk2 as
indicated.  

You might be able to configure sdb, but if you do, do not set the
partition type to fd until _after_ you finish installing ubuntu.  If you
must do this, set the partitions to type 83.  Note that I did not do it
this way, but I'll try it on the next install.

Since the first disk was partitioned with the installer, and the second
with fdisk, their ideas of a partition size like +200M didn't exactly
match.  I went into fdisk /dev/sda, changed the display to 'sectors'
(with the 'u' command) and then printed the existing partition table.
Then, when partitioning the /dev/sdb, I used the exact from and to
sector numbers to ensure that my partitions would be the same size.

The other thing that tripped me up is the grub entries in menu.lst. 
I've no experience with grub, so I was thrown by the setup and
terminology.  The terminology refers to 'root (hd0,0)'.  I took that to
mean the root FILESYSTEM location, which according to the directions, I
thought would be /dev/sda6 (or hd0,5 in grub terms).  It's *NOT*, it
means the drive and partition where the kernel and initrd files are
stored.  Doh.

My menu.lst file looked something like:

title Ubuntu linux kernel xxx
root (hd0,2)
kernel /boot/vmlinux-xxx
initrd /boot/initrd.img-xxx
savedefault
boot

It took me awhile to figure out that because boot is on it's own
partition that not only did I have to change the 'root' directive, but
also that there is no /boot subdirectory:

title Ubuntu linux kernel xxx
root (hd0,0)		<----- The 'boot' partition
kernel /vmlinux-xxx	<--- These are on the root of the boot partition
initrd /initrd.img-xxx	<--- Thses are on the root of the boot partition
savedefault
boot

Once I figured out that simple bit and could get the system rebooted
onto the degraded md array, the rest of the instructions were easy to
follow.

Be sure to regenerate initrd.  There is a question in the text as to
whether it is still needed.  I ran it to another file, and then did a
diff over the two versions.  Since they came out with differences, I
conclude that it's best to be safe and regenerate.

The kernel messages during boot were indicating 'swap area shorter then
signature indicates'.  I ran mkswap /dev/md1 and rebooted.  Now, I see
that the kernel messages indicate 'Adding 979832k swap on /dev/md1', so
watch out for that.

--
Regards,
Rich

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