Re: Clon disks with dd command

[Alejandro <alejandritox@ciudad.com.ar>]

Bob and other people, thanks for your response, it's very important to me.

But I have my last short question:

Is it possible to use "dd" if I have to disks with the same size but
different models like this:

Disk A:
description: SCSI Disk
product: SAMSUNG SP0812C
vendor: ATA
physical id: 0.0.0
bus info: scsi@0.0:0.0
logical name: /dev/sda
version: SU10
size: 74GB
configuration: ansiversion=5

Disk B:
description: SCSI Disk
product: ST380013AS
vendor: ATA
physical id: 0.0.0
bus info: scsi@0.0:0.0
logical name: /dev/sda
version: 3.43
size: 74GB
configuration: ansiversion=5

Thanks a lot,

alejandro.-


Bob McGowan escribió:
> Short answer:  yes, that will work.
> 
> Longer:  showing example from my system.
> 
> # dd if=/dev/sda of=sda-blocks bs=1024 count=4
> 4+0 records in
> 4+0 records out
> 4096 bytes (4.1 kB) copied, 0.0101397 seconds, 404 kB/s
> # ls -l
> total 4
> -rw-r--r-- 1 root root 4096 2006-12-21 08:33 sda-blocks
> # file sd*
> sda-blocks: x86 boot sector; partition 1: ID=0xfd, starthead 1,
> startsector 63, 585922617 sectors, extended partition table (last)\011,
> code offset 0x48
> 
> I copied the first 4K from my boot disk to a file using dd, and then
> used 'file' to show that it has the:  1.  x86 boot sector; 2.  partition
> information, including some data about the extended partition table.
> 
> You should probably use the 'bs=' option to 'dd', to speed it up.  In
> cases where I've done this sort of thing, I've used block sizes that are
> even multiples of the 'native' size.  You do need to be sure not to use
> up all of your available RAM with a size that's too big ;)
> 
> I've found that 'bs=10k' seems to work well, though if you have plenty
> of RAM you might want to try something bigger.
> 
> Bob
> 
> Alejandro wrote:
>> Hi all, I have a Debian Etch machine with a SCSI HD as a master disk. I
>> want to make a clon to another similar SCSI HD (same model and size), in
>> order to use it if the production disk fails.
>>
>> People talk about "dd" command, telling it's possible to get a exact
>> mirror from one disk to another just running this:
>>
>> dd if=/dev/sda of=/dev/sdb
>>
>> Is this just the solution ??? No matter with the MBR or something else
>> ???
>>
>> Really thanks,
>>
>> alejandro.-