[gentoo-user] Re: Moving the system from one disk to another

[Kerin Millar <kerframil@gmail.com>]

On 05/04/2010 02:34, walt wrote:
> On 04/04/2010 01:04 PM, Neil Bothwick wrote:
>> On Sun, 04 Apr 2010 20:35:11 +0100, Kerin Millar wrote:
>>
>>> Whichever way you go about it, ensure that no pseudo-filesystem or bind
>>> mounts are present within "/mnt/oldrootfs" at the time.
>>
>> Use the -x option with rsync to stop it descending into other
>> filesystems.
>
> This is directed to all of you gurus who replied to Meino's post:
>
> Meino's unstated assumption is that his new (larger) disk is already
> formatted
> (possibly partitioned?) before he copies the existing filesystem to it.
>
> IIUC the new disk will then be unbootable until grub or equivalent is
> installed
> on the new disk. Does this seem correct, or not?

Absolutely correct. Two commands from the grub shell and job done :)

>
> My instinct is to use dd to duplicate the entire old disk to the new
> (unformatted)
> disk and then use gparted to twiddle it from there. (But I do love a
> puzzle ;o)

In general, I'm a proponent of copying filesystems, as opposed to 
copying entire block devices or disks. That's not to say that there 
aren't some situations where the latter approach makes sense.

Note that it's possible to copy just the portion of the first sector 
that contains bootloader code as thus:

   dd if=/dev/sda of=/dev/sdb bs=446 count=1

NOTE: that's 446 as opposed to 512 as the latter would result in the 
partition table being copied too, which would be most undesirable.

Cheers,

--Kerin