[SOLVED]Datadump, dd-backup-restore-partition

#10:44 17/09/2015
#http://www.inference.phy.cam.ac.uk/saw27/notes/backup-hard-disk-partitions.html


#Copying partitions under linux
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#When making an image of a disk/partition, you don't want the drive contents changing under you, so the partition(s) must be either unmounted or mounted read-only. The latter possibility means that you can probably drop down to single-user mode and remount essential partitions read-only in order to backup a linux system. If you do this, make sure you have a way of restoring the backup which doesn't depend on already having the OS installed!

#A more general method is to boot from CDROM into linux without using the hard disk at all, for example using Knoppix. It's brilliant at autodetecting hardware.'

#Once you have a linux running, the basic technique is to use the dd command to read the hard disk device (or one of its partitions). The output of dd can be written to a file (perhaps to an external hard disk you have mounted) or piped over the network to another instance of dd on a remote machine. Note that there is a neater way of backing up NTFS partitions: see below.

#Example:
dd if=/dev/sda1 bs=1k conv=sync,noerror | gzip -c | ssh -c blowfish user@hostname "dd of=filename.gz bs=1k"







#Restoring partitions
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#The restore procedure is fairly similar. For example, on the machine with the image on it, you might do something like:

#Example:
dd if=filename.gz | ssh -c blowfish root@deadhost "gunzip -c | dd of=/dev/sda1 bs=1k"

This assumes you have linux (e.g. Knoppix) running on the target machine with an ssh server running. See 'Knoppix tips', below. Note that you should not include conv=sync,noerror in the restore dd - doing so can, in certain situations, corrupt the data being written, since it instructs dd not to wait for more data to arrive from the network or filesystem if a whole block isn't available.

#The partition needs to already exist before you do this, and needs to be large enough to take all the data. If it's too big, that doesn't matter, you'll just be wasting space at the end. You should then be able to grow the filesystem to fill that extra space. For ext2 filesystems, try using the ext2resize tool. You may also be able to persuade the partition editing tool parted to do this, since it can handle resizing most filesystems.