Is dd ok?

[Klaus-Peter Schrage]

Net Llama! wrote:
> On 03/21/04 09:17, Leon Goldstein wrote:
> 
>> Klaus-Peter Schrage schrieb auf Englisch:
>>
>>> My wife's got an old IBM 350 MHz PII machine with a 6 G IDE harddisk. 
>>> It is partinioned for dual booting with Grub to Win98 SE and RH 9 
>>> (which, alas, she uses very rarely - she's quite content with the few 
>>> apps she uses in Win98: Winword, Excel, Mozilla mail and browser).
>>>
>>> As you might imagine, diskspace is running short sooner or later with 
>>> such a setup on 6 G, so we bought a new 40 G harddisk which I plugged 
>>> in as secondary master in order to copy over the entire stuff. As the 
>>> disk was rather cheap and I was rather daring, I booted my knoppix 
>>> cd, checked if /dev/hdc was recognized and gave:
>>>     dd if=/dev/hda of=/dev/hdc.
>>> dd buzzed for about one and a half hour, and after it had finished I 
>>> was rather surprised to have all the partitions copied from hda to 
>>> hdc, no error messages, and all fscks were ok.
>>>
>>> After I had removed the old disk and put the new one in place, there 
>>> was Grub, I could boot into either OS without any difference (only 
>>> quite a lot faster due to the new disk).
>>>
>>> Now, has this been TOO easy? I found nothing on the net about doing 
>>> such a foolish thing or any caveats (differing geometries etc.).
>>
>>
>>
>> I would like to clone a drive that has run out of space to a bigger 
>> one.  Will Klaus-Peter's procedure duplicate the existing partitions' 
>> original size on the new drive, or will they expand proportionally to 
>> fill it?
> 
> 
> It should replicate the existing partitions.  You'd then have alot of 
> extra space where you could create additional partitions.
> 
>>
>> If dd only duplicates the original partition's size, could I partition 
>> the target drive before running dd?
> 
> 
> No, dd will overwrite the partition table, and all pre-existing data 
> structures on the new disk.

When you create newbigpart and dd oldlittlepart into newbigpart, than 
you get different size infos:
- df tells: available size of newbigpart = size of oldlittlepart
- fdisk -l tells: size of newbigpart is preserved.
Klaus