Rsync/Full system backup
From ArchWiki
This rsync script allows creating a full backup copy across filesystems. It is setup so that the copy includes intact booting capabilities, optionally excluding selected files.
The approach has benefits over omitting system files by just copying personal data; if the system becomes corrupted in the main partition, overcoming the problem means booting into the backup as opposed to identifying and reinstalling affected programs.
Instructions were converted from this forum post.
Contents |
Files
Two files are needed: the backup script and a file stating which files to include/exclude from the backup source.
Backup script
The script is very simple; it rsyncs in archive mode, ensuring that symbolic links, devices, permissions and ownerships, among other file attributes are preserved, while excluding files that match the patterns from the include/exclude list.
Save it as rbackup.sh and make it executable:
#!/bin/sh # rsync backup script sudo sh -c " rsync -av --delete-excluded --exclude-from=backup.lst / $1; touch $1/BACKUP "
- Backup source; /
- In this case it's performing a backup on the whole root.
- Backup destination; $1
- Passed as an argument to the script; e.g. /media/backup
- Include/exclude list; --exclude-from=backup.lst
- This example uses backup.lst.
Include/exclude list
As deciding which files should populate this list can be difficult, here's a typical backup example that excludes common files that don't need to be backed up, such as the vast majority of /dev. Note that specifying every desired file or directory in Include is not needed; this section only acts as a filter for statements in Exclude. This file is in the traditional include/exclude rsync format.
Save the following as backup.lst:
# Include + /dev/console + /dev/initctl + /dev/null + /dev/zero # Exclude - /dev/* - /proc/* - /sys/* - /tmp/* - *lost+found
- Exclude
- Content in system directories; /dev, /proc, /sys and /tmp are excluded because they are created by the system at runtime, while the directories themselves need to be preserved since they are not regenerated at boot. Lastly, all lost+found instances are skipped since they are partition-specific.
- Include
- Even though /dev is excluded, 4 files that are not dynamically created by udev need to be preserved. These are console, initctl, null and zero.
Backing up
Substitute /media/backup as appropriate, and mount the destination device:
# mount /dev/sdb1 /media/backup
Run the backup script (note that the trailing "/" character is necessary):
# ./rbackup.sh /media/backup/
Boot setup
After the sync is finished, the backup destination's /etc/fstab has to be modified, a boot loader needs to be installed on the backup destination, and configuration in the destination's /boot/grub/menu.lst requires to reflect the new location.
Modify fstab
Edit the backup destination's fstab:
none /dev/pts devpts defaults 0 0 none /dev/shm tmpfs defaults 0 0 /dev/sda1 /boot ext4 defaults 0 1 /dev/sda5 /var ext4 defaults 0 1 /dev/sda6 /mnt/prg ext4 defaults 0 1 /dev/sda7 / ext4 defaults 0 1 /dev/sda8 /home ext4 defaults 0 1 /dev/sda9 swap swap defaults 0 0
Because rsync has performed a recursive copy of the entire root filesystem, all of the sda mounpoints are problematic and will cause the backup boot to fail. In this example, all of the offending entries are replaced with a single one:
none /dev/pts devpts defaults 0 0 none /dev/shm tmpfs defaults 0 0 /dev/sdb1 / ext4 defaults 0 1
As before, remember to use the proper device name and filesystem type.
Install bootloader
While these instructions assume GRUB is being employed, they could easily be adapted to other bootloaders, such as lilo.
Open the GRUB console:
# grub
Direct the install towards the destination device:
root (hd1,0) setup (hd1)
- root; hd 1,0
- This should point to where the GRUB files are located--in this case, "hd 1" means the second storage device (/dev/sdb) and "0" is the first partition (/dev/sdb1).
- setup; hd 1
- The command specifies where the actual boot loader is to be installed. In this example it is installed to the MBR of the second storage device.
Configure bootloader
The problem here is that even though the boot loader installs correctly, its menu entries are for the main system's partitions, not the backup system's.
It's possible to fix this by creating a custom /boot/grub/menu.lst for the backup destination. In order to do this, modify rbackup.sh so that it copies a custom menu.lst:
#!/bin/sh # rsync backup script sudo sh -c " rsync -av --delete-excluded --exclude-from=backup.lst / $1; cp ~/custom.menu.lst $1/boot/grub/menu.lst; touch $1/BACKUP "