New subject: [opensuse] Copy One Hard Drive To Another Hard Drive(Backup)?

24 Apr 2013

      On Wed, Apr 24, 2013 at 2:15 PM, Greg Freemyer 
wrote:
...
On Wed, Apr 24, 2013 at 1:57 PM, Mark Hounschell  wrote:
...
On 04/24/2013 01:50 PM, Dsant wrote:
...
Le 24/04/2013 19:35, Mark Hounschell a écrit :
...
On 04/24/2013 12:21 PM, Dsant wrote:
...
* dd is not safe.
* For such a size, avoid graphical tools.
* So prepare your partition, and use rsync instead :
rsync -r -P -t --progress source destination
Could you explain why "dd is not safe"?
mark
Tell me if I am wrong, but dd does not know about partition format
consistency , files and folders, or checksums. So if you have the choice
between dd and rsync, rsync will complain if CRC is wrong.
The best would be that the tool would re-read what have been written, as
for CD-RW.
It does not know or care about "about partition format consistency ,
files and folders, or checksums". It does a sector by sector copy. The only
problems I know about are when the 2 disks are not of the same size, and or,
when the original disk is a "system" disk and the OS is configured for other
than by device name. Even then it's easy to make it right.
Mark
I believe Dsant is looking for something like:

read source and calculate CRC/hash
write dest
read dest and verify CRC/hash

Errors do occur that cause the copy to be corrupt and thus for verify to
fail.  In my experience it is a hardware issue of some kind (bad disk,
cables, ram, power supply, etc.)

I have nothing against rsync, but if you want/need functionality like the
above, the ewftools package I mentioned can also do it. ewfacquire is
a tool that
will copy all the sectors of a physical disk into a large file.  It does add
CRC/hash info to the "image" file.  It also will break the image file up
into segments.  I have used 2GB segments very often, so a 500GB drive image
would require 250 segment files to hold it.

It also supports multiple compression levels, so it often compresses
down pretty significantly.

To verify the image still is an accurate copy of what was read you can use
ewfverify.  It will verify the CRCs and an overall hash.  To restore the
image, ewfexport.  To just work with the image as if it was one large file
like a simple dd to a file would create, you use ewfmount.

Greg
...
-- 
To unsubscribe, e-mail: opensuse+unsubscribe@opensuse.org
To contact the owner, e-mail: opensuse+owner@opensuse.org

Re: [opensuse] Copy One Hard Drive To Another Hard Drive(Backup)?

Greg Freemyer

Carlos E. R.

Greg Freemyer

Carlos E. R.

Carlos E. R.

tags

participants (2)