Corrupted sd card/ make mirror image for back up

[Liggerstuxin]

You'd think that I could install 1channel and navi-x lightning quick considering how many times I've one it... Yet every time something like xbmc maintenance won't work on the first try, and some how I always need to reset, and reinstall and retry something....

Here's the question, it's an easy one,

How do I make a mirror image of my card for easy copying, when my card gets corrupt/glitched. ( I'm on my seccond class 4 card, I shoulda bought a high class one the seccond time... With my 512 raspberry)

It seems like as soon as I get xbian with all the bells and whistles, something goes wrong and freezes. And stupid xbmc maintainable repo is being inconsistent.

Thanks for all they help guys