I regularly back-up my Raspberry Pi storage card because it’s so easy to damage the card with an improper shutdown or some such. I back up to a Mac, and you can read how I do it here. This wasn’t much of a chore in the early days when I was working with 4GB cards, but now I use 16GB Micro SDs and I know of folks who have much, much larger storage capacities thanks to never-cheaper cards. All this means the back-up takes a long time. So I wondered if I could create a gadget to tell me the task was done, allowing me to get on with other jobs in the meantime.
I’ve re-installed my Pi’s SD card storage more times than I care to recall. New cards, programming glitches, messing with Linux’s settings files – all of these reasons have forced me to go through the process of re-flashing the Pi’s storage card. That’s bad enough – what’s worse is having to re-download the applications I’d added since the previous install, applying updates and choosing again all of my system preferences.
What I should have done was clone my card, allowing me to re-flash the SD card with a complete, working and configured to my personal satisfaction Pi operating system.
I don’t know why I didn’t do this. I suppose Mac OS X’s inability to cope with the Pi’s EXT4 file-system was the main reason: I can’t simply drag and drop the card’s contents, first to the Mac and then, later, back to a freshly formatted card. But a little Googling set me on track to use the next best thing: the
dd command, available in OS X – and Linux for that matter.