backup partition

[Matt Graham]

> Derek Trotter writes: 
>> I'm looking for something on linux that would allow me to create
>> image files to back up partitions.
From: "kitepilot at kitepilot.com" <kitepilot at kitepilot.com>
> dd if=/dev/sdXY of=my_backup 
> Recover with: > dd if=my_backup of=if=/dev/sdXY 
> I'd go with tar though.  Simple and bulletproof...

tar is not appropriate for the general case.  There are things that tar cannot
back up and restore properly, like files which have absolute sector positions
and filesystem metadata that tar doesn't know about.  You find those things on
NTFS partitions, HFS+ partitions, /boot when LILO is being used, and the slack
space between the boot record and the start of the first partition when GRUB
is being used.

dd will *work* for the general case, but it's inefficient, especially the way
you wrote the commands above.  dd copies every block, including those blocks
that don't need to be copied.  Since you left the bs= off, it also uses a
block size of 512 bytes, when you should be using bs=32k or bs=64k.  partimage
knows enough about most filesystems to only copy the blocks that are actually
in use, and to retain sector position info.  partimage also has an ncurses
interface, which is a little better-looking and more friendly than dd.

-- 
Matt G / Dances With Crows
The Crow202 Blog:  http://crow202.org/wordpress/
There is no Darkness in Eternity/But only Light too dim for us to see