Re: [PLUG] How best to replace old drive with new drive - problems installing grub

[jondz <linux@jondz.net>]

Hi

Ok this is an old thread but I also decided to clone a disk  tonight.
Writing most of the stuff down that I can remember.  Could have some
ideas useful to somebody later.  In no particular order and might have
some errors and i wont be really sure until i yank the old drive out.


My target -- I decided to replace an IDE drive (/dev/hda) with a SATA
drive (/dev/sda).  I really didnt like the way two drives are chained on
the one channel that the motherboard had.

so..

with /dev/sda still fresh,


1. create /dev/sda1 that is exacly the same size as /dev/hda1
2. reboot in single user
3. mount -o ro,remount /
4. dd from hda1 to sda1
5. fsck /dev/sda1 

Now the tricky part (here is where I had to reboot many many times, so
this is a summary of what i think should have been done if i had only
one try)

mount /dev/sda1 /mnt/tmp/
edit /mnt/tmp/etc/fstab so that root points to /dev/sda1
edit /mnt/boot/grub/device.map # change /dev/hda to /dev/sda
edit /mnt/boot/grub/menu.lst # change kernel params root=whatever to
root=/dev/sda1

grub command line (this is where i googled the stuff and wrote it down
on my cellphone because it is so useful) (I think what this does is
pretend that /dev/sda is the first disk):

device(hd0) /dev/sda
root (hd0,0)
setup (hd0)

set bios to boot on the sata disk

now the machine is booting with root on /dev/sda1 and with the rest of
them still in /dev/hda.  Usually i clone a filesystem one by one with
occasional /etc/fstab editing and reboots.   For example i am
cloning /usr right now.  I do not clone bit-by-bit for anything other
that root, what i do is

fdisk /dev/sda # create partition for /xyz
mkfs.ext3      # rarely used very fun to use command
mount /dev/sda2 /mnt/tmp/xyz

cd /
tar cvfp - xyz  | ( cd /mnt/tmp/ && tar xvfp - ) # VERY DANGEROUS 


I am now in a situation where update-grub and grub-install is not yet
clean (there is a UUID attribute of the partition that gets in the way
which i dont care about).  Plus, there is the possibility of the machine
actually booting off the original disk still.    Should be resolved when
i remove the original /dev/hda.  

jondz















On Sat, 2007-10-20 at 19:39 -0400, Mike Leone wrote:
> So here's what I did:
> 
> installed new HD
> booted knoppix in command line only (knoppix 2)
> mkdir /mnt/oldhd
> mkdir /mnt/oldhd/boot
> mkdir /mnt/oldhd/usr
> mkdir /mnt/oldhd/var
> 
> mount /dev/hda5 /mnt/oldhd
> mount /dev/hda1 /mnt/oldhd/boot
> mount /dev/hda7 /mnt/oldhd/usr
> mount /dev/hda8 /mnt/oldhd/var
> 
> chroot /mnt/oldhd
> /usr/sbin/grub-install hd0
> 
> It said:
> 
> Could not find device for /boot: not found or not a block device
> 
> Had no errors mounting it; if I changed to it, I saw all the proper
> files in /boot.
> 
> Thoughts?
> 
> (there's reasons why I dislike computers ... :-))
> 
> 
> (/boot is ext2; all others are ext3. Not that it should matter; mount
> auto-figured out what the format was, else I wouldn't have seen anything)
> ]
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