Raspberry Pi SD Backup

I'm breathing a little easier today after backing up the SD card in my Raspberry Pi. I realized there was a problem while I was at Starbucks and tried to connect to my home VPN... no joy. When I got home I found the Pi sitting with a single red light. This happened once before. The last time it was after a power outage and it seems that was the case this time, too. I had no success reviving the thing, but just like last time, re-flashing the OS onto the SD card did the trick. Well, sort of... I still had to re-install and configure openvpn, setup 2-factor authentication, etc.

I suspect the issue is related to the power supply I'm using. It's a Motorola PSU that I had on hand; 5V 550mA ... a little on the low side, but I've got nothing connected via USB so it seemed to work OK.

I jumped on Amazon and picked up a new power supply

and another SD card

The steps below are for Mac OS X.

To create a backup of the SD card:

  • Launch Terminal
  • Issue the following command
    • diskutil list
  • Note the disk number of the SD card. It has a FAT32 and a Linux Partition. In my case it was /dev/disk1.
    • !! It's important to get this right. If you use the wrong disk number, you could lose data on your hard drive !!
  • Issue the following command (substituting the appropriate number of your SD disk)
    • sudo dd if=/dev/rdisk1 of=~/Desktop/pi.img bs=1m
  • This accesses the raw disk and writes it to an image file on your desktop. There's no progress display, so just wait until it finishes. It will take several minutes.

When you're ready to restore the image:

  • Unmount the disk
    • sudo unmountDisk /dev/rdisk1
  • Restore the image to SD
    • sudo dd of=/dev/rdisk1 if=~/Desktop/pi.img bs=1m


on 2014-06-16 23:57 by R Keith Smith

So, we had a power outage a couple of days ago. Actually about 2 or 3 in quick succession where it seemed like things would recover then they went right back off. Anyway, I forgot to check on the Raspberry Pi to see if it had booted back up and was working now with the new and improved power supply. I'm at a Starbucks right now and just connected to it as usual so it seems that the power supply really did the trick.