How to duplicate a HD using dd

[Robert L Cochran]

Well you know, there IS a Hard Drive Upgrade How To on the LDP. It gives 
every needed detail. I've done it 3 times now and generally move up to 
bigger drives that way.

Bob

Willem Riede wrote:

> On 2003.10.11 18:44, Thiago Vinhas de Moraes wrote:
> 
>>Em Sáb, 2003-10-11 às 19:16, jdow escreveu:
>>
>>>From: "Thiago Vinhas de Moraes" <tvinhas at techbyte.com.br>
>>>
>>>>Sory for the OT, but does anyone the best way to duplicate a HD in
>>>>Fedora, just like Norton Ghost does in Winblows? 
>>>>
>>>>I tried to use dd if=/dev/hda of=/dev/hdb, but the proccess has never
>>>>stoped, after a few hours. 
>>>>Both are 40Gb hard drives, but from different manufacters. One is a
>>>>Maxtor, and the other one is a Samsung.
>>>
>>>If the drives are basically the same size with the destination drive
>>>being the larger drive if you elect to waste some drive, then the
>>>dd approach is the fastest. However it is best to add a suitable
>>>"bs=8225280" or if you don't wish to be so profligate with memory
>>>"bs=131072" should be nearly as fast.
>>>
>>>"dd if=/dev/hda of=/dev/hdb bs=131072", for example
>>
>>What's the difference between "bs=8225280" and "bs=131072" ?
>>
>>I tried without the "bs" and when booted with the copied drive, got
>>infinite fsck problems that I don't have with the original hd. Do you
>>know why?
> 
> 
> Even though the two drives are about the same size, they probably have 
> different geometries (number of cylinders, etc.). That means that the
> partition table that you copied with 'dd' is not going to work.
> 
> You may be able to set up partitions manually on your new hd that are 
> no smaller that those on your old drive that have data you need to copy 
> (swap is an example of one you don't want to copy), and then do 'dd' 
> partition by partition (hda1 to hdb1, etc.).
> 
> The bs= parameter determines how much gets read from drive one before
> switching over to drive 2 and writing. Too small a size makes 'dd' 
> inefficient. If this is all that you are doing on your PC, you can use
> a good bit of memory, such as 8M (I like powers of 2 -- this is not
> exactly the same size as suggested above, but close).
> 
> Success, Willem Riede.
> 
> 
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> 

-- 
Bob Cochran
Greenbelt, Maryland, USA
http://greenbeltcomputer.biz/