How to duplicate a disk

[Les Mikesell]

On Sat, 2005-10-29 at 05:22, LinuxMedia wrote:

>  >The thing I was really trying to stress is that "dd" is not a good tool
>  >to use _unless_ the source and target drives are the same make and >model
>  >as "dd" does a block-by-block copy...and that includes the partition
>  >table and boot sector.  If the drives don't match up, you could end up
>  >with a mess.  That holds even for drives in LBA mode on some systems
>  >with weird BIOSes.
> 
> I completly forgot about all these considerations. Would it suffice to 
> just have two drives that are the same size? Or would that even be 
> taking a chance? I remember being very careful to get the same makes of 
> drives just in case there were slight difference is Brand X's 40 Gig 
> drive and Brand Y's 40 Gig drive.

An 'fdisk -l' should show the drive geometry.  If the
heads/sectors/cylinders match on the drives a dd
clone should work find.  However there are some identifiers
on raid and LVM volumes that may cause trouble if two
cloned drives are ever connected in the same machine
at boot time, and I don't think the previous discussion
mentioned the filesystem labels that are used in fstab
and grub by default.  If you clone with dd, these are
reproduced identically and will work in another machine
by will prevent booting when you have duplicates connected.
If you copy with one of the other methods you either
have to add the filesystem labels yourself or edit
/etc/fstab and /boot/grub/grub.conf to use the
partition device names.

-- 
  Les Mikesell
    lesmikesell at gmail.com