Grub dd?

[Peter Xu]

Hi, Grub list,

I found there's no "dd" command for grub.  Is there a reason?

Asked because I think it could be really handy to be able to do that 
with grub.  For example, a simple use case is we can backup root 
partition somewhere on a backup disk before hand, then if the real root 
partition corrupted for some reason we can always dd it back within grub 
loader.  It could be helpful when it's non-trivial to attach a USB live 
image to the system so we can't initiate "dd" in a live Linux distro.

I'm actually thinking of some way to allow the root fs to be recovered 
from a "snapshot" by dd-ing from a backup block device before loading 
linux and everything, for every single time the system boots.  Then we 
guarantee every time we boot into the system we'll always see the same 
content for root fs.  Not sure whether that can be easily done with 
current grub.

Thanks,

--
Peter Xu