How to mirror a harddisk for backup purpose

[Kwan Wing Keung]

On Fri, 22 Jun 2001 alvin at Mail.Linux-Consulting.com wrote:

> 
> hi kwan
> 
> i would use tar to copy disks onto antoher disk...
> 
> #
> # copy hda  onto hdb...
> #
> dd if=/dev/hda  of=/dev/hdb bs=1024
> 
> BUT..BUT...dd is bad ...
> 	- it copies bad block info fron disk-a onto disk-b
> 	- it does NOT know that disk-b has bad sectors where it was
> 	  good on disk-a
> 	- it copies all the empty unused space onto the 2nd disk
> 	  unless you tell it NOT to copy all of the partition
> 	  in which case you are assuming that you know where all
> 	  the bits are for a given file/inode tree

THANKS!!!  May I know what is your preferred mirror method?

In my LINUX PC, I already have 2 identical harddisks 
C: and D: (in MSDOS terminology).


kwan