DD not working--SUCCESS!

Karl Larsen k5di at zianet.com
Sat Sep 1 21:23:03 UTC 2007


    Here is my final paper on using dd. Feel free to shoot at it.


    If you want to copy something big from one partition to another the 
old dd method is for you. You have to do it right. This means that:

1. The destination partition MUST be as large or larger than the source 
partition where the data is coming from. This is essential!

2. The dd copies everything including the file system.

3. Be ready to check the file system of the copy with fsck.

4. If you are making a copy of an entire working Fedora system make sure 
you change all the entries in /etc/grub.conf and /etc/fstab files to the 
new partitions of the copy before you try to run it.

5. To copy a partition from the source, called /dev/source to a 
destination partition called /dev/destination use the standard dd form:

    # dd if=/dev/source of=/dev/destination

6. Make certain that all Hard Drives are registered in bios. Put the F7 
Rescue CD in, or your F7 DVD in, and select Rescue. When it asks if you 
want to mount your fedora system do not just go to the Prompt. At the 
prompt do your dd transfer.

7. Take your time doing all this. It will save you problems later. There 
are a lot of ways to make errors.

8. Think of how dd works this way, dd see's the source partition as just 
a pile of bytes. It takes a few bytes each cycle and puts those bytes on 
the destination partition. When done dd reports how many bytes it found 
and how many it put on destination. They are the same large number.

9. The default number of bytes per Block is defaulted to 150. The info 
DD says this:
 `bs=BYTES'
     Set both input and output block sizes to BYTES.  This makes `dd'
     read and write BYTES per block, overriding any `ibs' and `obs'
     settings.
So if in a hurry you can use bs=15000 which will be a good thing because 
the IDE hard drive controllers are quite slow. So rather than sending 
just 150 bytes per change, you send 15,000. A transfer will look like:

    # dd bs=15000 if=/dev/sda6 of=/dev/sdb5

I have not tried this. No reason to think it will not work.





-- 

	Karl F. Larsen, AKA K5DI
	Linux User
	#450462   http://counter.li.org.




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