How to backup your disk with dd
I had several bad experiences losing my data in my life. Sometimes because of the hardware, sometimes because of my stupidness or inexperience. At least, it learned to be careful. I backup my data regularly, and on several support concerning the important ones.
I sometimes back up my primary partition, where the system is set. If my drive crashed, I want to recover quickly a system without having to reinstall hundreds of applications. I have used several times Partimage and was satisfied. But now I tend to use dd, which basically do the same thing in just one line. The advantage is that it is by default on any Linux distribution.
To back it up on an usb disk :
$ sudo dd if=/dev/hda1 | gzip -v | dd of=/media/usbdisk/backup_hda1.gz
To backup my home and other data partitions, I just copy the files manually, it is faster and there is no need to backup such a thing as the boot sector. But of course you could use the same command above.
When you wish to restore the partition to a new hard drive, just :
$ zcat /mnt/hdb5/sauvegarde.gz | dd of=/dev/hda1
To do that, you will have probably booted on a live CD Linux as Knoppix to restore the crashed system. In any case, don’t overwrite the system you just booted on !
One tip if you want to back up only the boot sector :
$ sudo dd if=/dev/hda of=/home/secteur_boot.dd bs=512 count=1
And to restore :
$ sudo dd if=/home/secteur_boot.dd of=/dev/hda bs=512 count=1