[mythtv-users] Clone MythTV HDD

[Jarod Wilson]

On 08/04/2009 08:29 PM, Jay Foster wrote:
>> On 08/04/2009 08:07 PM, John Drescher wrote:
>>>> I wouldn't trust dd unless the partitions are
>> *exactly* the same size.
>>> dd is perfectly fine as long as the destination is the
>> same size or
>>> larger. I have used dd at work dozens of times to move
>> a drive to a
>>> larger one. After this you can use fdisk to extend the
>> partition and
>>> then use the appropriate fs tool to grow the
>> filesystem.
>>
>> Personally, I prefer manual partitioning of the new disk,
>> then mount all
>> partitions of the old disk in one place, all the partitions
>> of the new
>> disk in another, then just rsync between the two. (With
>> neither being
>> actually booted at the time -- a live CD is great for
>> this).
>>
> I tend to agree with this approach too.  I have used the dd method successfully, but there are a few things to look out for.  I think some (all) file systems keep a bad blocks list.  When you use dd, you copy that list too.  Perfectly good blocks on the new drive may be marked bad, and even worse, the reverse situation.  A new partitioning and formatting eliminates this possibility and provides the oportunity to change the partition sizes up front.

I do it more for the benefits of a freshly formatted file system, which 
sometimes includes enabling of features not previously enabled (also 
provides the opportunity to move to a new fs, like ext3 to ext4), and in 
theory, your new disk has the data laid out in a less fragmented 
fashion. Hadn't considered any badblocks-related possibilities.

-- 
Jarod Wilson
jarod at wilsonet.com