Evolution of a Blog

This blog has evolved as I have as a maker. It starts at the beginning of my journey where I began to re-tread my tires in the useful lore of micro electronics and the open-source software that can drive them. While building solutions around micro-electronics are still an occasional topic my more recent focus has been on the 3D Printing side of making.

Tuesday, September 25, 2012

Backing up the Raspberry Pi

The code base for the Robot lives upstream from the RPi and is downloaded on update but there is a fair amount of other configuration that goes into the Raspberry Pi that really needs backing up!   Having done a re-install once already...I know this!

The easy way to do a backup is to copy the entire SD card.  You can do this from the RPi if you have a second card reader but between the speed of the Raspberry and the speed of the cards this makes a slow process even slower.   I make my backups on my Ubuntu machine as follows.

Insert your SD card and find out what the two device names you need to backup:

First Way:  Use the 'dd' command to make a full backup from the SD card to your hard drive (this will take a while):

Second Way:  Instead of using dd you can just do a cp (it will actually be quicker than dd if your disk is less than full but slower if your disk is more full than empty).  In the example below I have positioned myself in a sub-directory within which I want my backup to reside:

    sudo cp /media/10b4c001-2137-4418-b29e-57b7d15a6cbc . -r

The problem with the second way is that everything comes across in a restore as being owned by root.   I think, but could be wrong, that dd preserves ownership?  In any case I only use the default user of 'pi' so fixing this is easy:

    sudo chown -R pi .

What I wonder about both of the above is...does it really yield a perfect replica if I had to do a restore?   I am not sure that it would given rights in the second case.

1 comment:

  1. Type man cp or cp --help. You can prserver overship and attributes (suid, sgid) without your backup is useless.