Restore individual files/directories from a backup

Sometimes a complete restore of the entire system is not required, but only individual file(s) or directories. This is not directly supported by raspiBackup. Since raspiBackup only uses standard Linux tools to restore the entire system, this can be done manually for all backup types.

However, these activities must be carried out on a Linux system.

The easiest way to do this is with rsync backups. dd and tar backups require a few additional steps on the command line.

dd backup

First, the dd image file must be made available.

In the following example, the USB disk partition is /dev/sda1 and is mounted to /mnt mounted with:

sudo mount -o ro /dev/sda1 /mnt

Search there for the desired backup generation and the image file.

Next, determine the sector offset in the image file with fdisk.

sudo fdisk -l raspberrypi-dd-backup-20160415-222900.img

Disk raspberrypi-dd-backup-20160415-222900.img: 7.5 GiB, 8011120640 bytes, 15646720 sectors
Units: sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes
Disk label type: dos
Disk identifier: 0x000798a3

Device Boot Start End Sectors Size Id Type
raspberrypi-dd-backup-20160415-222900.img1 8192 122879 114688 56M c W95 FAT32 (LBA)
raspberrypi-dd-backup-20160415-222900.img2 122880 15646719 15523840 7.4G 83 Linux

So there are 8192 for the first partition and 122880 for the second partition.

Now the partition is mounted after /media, in the example the second, the root partition. Note: The offset must be multiplied by the sector size, in this case 512.

sudo mount -o ro,norecovery,loop,offset=$((122880*512)) raspberrypi-dd-backup-20160415-222900.img /media

You can now access all the backup data in the /media directory.

ls /media/

backup boot dev home lost found mnt proc root sbin srv tmp var
bin boot.bak etc lib media opt remote run selinux sys usr

Unmount the partition to exit:

sudo umount /media
sudo umount /mnt

tar backup

First the tar file must be made available.

In the following example, the USB disk partition is /dev/sda1 and is mounted to /mnt with :

sudo mount -o ro /dev/sda1 /mnt

Assume that the entire directory /etc in the tar file is to be accessed. This can be done with the following command.

tar -xf raspberrypi-tar-backup-20171028-205746.tar -C /tmp etc

But you have to be patient, because depending on the size of the tar file, this can take some time.

Finally, the /etc directory has been extracted from the tar file to /tmp. Access is now possible there.

rsync backup

Access to the rsync backup directory must be available at the beginning.

In the following example, the USB disk partition is /dev/sda1 and is mounted to /mnt with :

sudo mount -o ro /dev/sda1 /mnt

The contents can now be accessed directly:

cd /mnt/backups/raspberrypi/raspberrypi-rsync-backup-20160705-212724-8G

ls -la

total 57592
drwxr-xr-x 26 pi pi 4096 Jul 5 2016 .
drwxr-xr-x 14 root root 4096 Apr 18 2018 ...
drwxr-xr-x 2 root root 4096 Nov 15 2015 backup
drwxr-xr-x 2 root root 4096 May 29 2016 bin
drwxr-xr-x 2 root root 4096 Jan 1 1970 boot
drwxr-xr-x 3 root root 4096 Apr 20 2014 boot.bak
drwxr-xr-x 2 root root 4096 Jul 4 2016 dev
drwxr-xr-x 125 root root 12288 Jul 5 2016 etc
drwxr-xr-x 3 root root 4096 Feb 1 2015 home
drwxr-xr-x 16 root root 4096 May 29 2016 lib
drwx------ 2 root root 4096 Dec 15 2012 lost found
drwxr-xr-x 2 root root 4096 Jul 3 2016 media
drwxr-xr-x 2 root root 4096 Jan 8 2014 mnt
drwxr-xr-x 3 root root 4096 Mar 1 2015 opt
-rwxr-xr-x 1 pi pi 126799 Jul 5 2016 pi
dr-xr-xr-x 2 root root 4096 Jan 1 1970 proc
drwx------ 2 root root 4096 Jul 10 2013 .pulse
-rw------- 2 root root 256 Dec 16 2012 .pulse-cookie
-rw-r--r-- 1 root root 58720256 Jul 5 2016 raspberrypi-backup.img
-rw-r--r-- 1 root root 512 Jul 5 2016 raspberrypi-backup.mbr
-rw-r--r-- 1 root root 273 Jul 5 2016 raspberrypi-backup.sfdisk
drwxr-xr-x 4 root root 4096 Aug 15 2013 remote
drwx------ 13 root root 4096 Jul 3 2016 root
drwxr-xr-x 2 root root 4096 Jul 5 2016 run
drwxr-xr-x 2 root root 4096 May 29 2016 sbin
drwxr-xr-x 2 root root 4096 Jun 20 2012 selinux
drwxr-xr-x 3 root root 4096 Mar 7 2014 srv
dr-xr-xr-x 2 root root 4096 Jul 4 2016 sys
drwxxrwxrwx 2 root root 4096 Jul 5 2016 tmp
drwxr-xr-x 10 root root 4096 Dec 15 2012 usr
drwxr-xr-x 12 root root 4096 Jul 8 2014 var