Change Disk from IDE to SCSI using dd, what else ?

[Sam Varshavchik]

Eduardo J. Vega A writes:

> Hello guys... I got already FC3 installed at /dev/hda but I need to move 
> it to /dev/scd

The first SCSI hard drive is /dev/sda.  There is no /dev/scd device, 
/dev/scd0 is the first SCSI CD-ROM drive.

> I know that I can move them by using dd, but, what else do I may need to 
> change ?

Quite a bit.

> 1) Grub ? Which config files ? Should I do any other stuff rather than 
> modify the new path at the Config files ?
> 2) FSTAB ?
> 3) Others ?

Grub is the least of your worries.  Depending on how you about doing this, 
all that will be needed to make grub happy is some monkeying around with 
device.map.

The tricky part is that you need to create a new initrd that loads the right 
combination of SCSI kernel modules.

I suggest the following approach, instead.  You don't need to get your hands 
dirty doing it this way.

1)  Jot down exactly what warez you have installed on your existing disk; 
specifically the fedora packages, and any RPMs you installed yourself.

2)  Disconnect your IDE drive, and attach your SCSI drive.  Take your Fedora 
CD or DVD set, boot it, and do a clean install of Fedora on your SCSI drive. 
When you select which packages to install, consult your notes and select the 
package set that matches what you already have installed.  Also, make note 
of which partition goes with which /dev/sd? device.

3)  Reattach your IDE drive, keep the SCSI drive connected.  When you 
reboot, you should boot off the IDE drive.  Most hardware boots IDE before 
SCSI. With some motherboards it's possible to get them to boot of SCSI 
first, but the interactions between that and Grub may not be pretty, so 
don't mess with it.

4)  You can then mount your SCSI drive as /dev/sd?, then copy your home 
directories and any non-system files you need to the SCSI drive. Disconnect 
the IDE drive permanently, and you will now have a clean system booting off 
your SCSI drive.

Do not try to copy your entire system from in step 4.  You have a good 
chance of turning the SCSI disk into an unbootable brick, if you're not 
really careful in avoiding the hotspots of /boot, /etc and maybe a few other 
places.  If you blow it, you'll need to start over from step 1.  On the 
other hand, you can use this as an opportunity to tweak the sizes of your 
partitions.  You do not need to partition the SCSI drive exactly like your 
IDE drive (which you would need to do, down to the last sector, if you were 
going to use dd).

If you've been a nice boy, if you've installed everything using RPM, and did 
not do anything by hand, all you need to do is get the same set of RPMs 
loaded on both disks.  If you manually mount the SCSI partitions in the 
right order, then you can open up a separate terminal window, chroot 
yourself to the root directory of the SCSI drive, and do a side-by-side 
comparison of what's installed on which box, with rpm.  So all you need to 
do by hand is copy the home directories.

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