# Full system backup with rsync

Related articles

- Backup programs
- rsync

This article is about using rsync to transfer a copy of your "/" tree, excluding a few select folders. This approach is considered to be better than disk cloning with `dd` since it allows for a different size, partition table and filesystem to be used, and better than copying with `cp -a` as well, because it allows greater control over file permissions, attributes, Access Control Lists (ACLs) and extended attributes. [1]

Either method will work even while the system is running. Since it's going to take a while, you may freely browse the web during this time. Worst case scenario you won't get the same opened tabs when you restore the backup (or boot from it) because they weren't saved. Not a big deal.

## With a single command

As root, run:

    # rsync -aAXv /* /path/to/backup/folder --exclude={/dev/*,/proc/*,/sys/*,/tmp/*,/run/*,/mnt/*,/media/*,/lost+found}

For information on why these folders were excluded, read the next section.

Note: If you are heavy user of hardlinks, you might consider using additionally `-H` `rsync`'s option, which by default is turned off as memory expensive during rsync run, but nowadays it should be no problem on most of modern machines. There are a lot of hard links below the /usr folder which save disk space.
Note: If you plan on backing up your system somewhere other than `/mnt` or `/media`, don't forget to add it to the list, to avoid an infinite loop. Also, if there are any bind mounts in the system they should be excluded as well, as not to copy the bind mounted contents twice. The example below is a good place to start and excludes all the necessary directories that are typically common to all users of Arch Linux. Your system may have additional areas which you may also want to exclude. Use the `mount` command to list system mounts for additional insight on what to exclude.
Note: You may want to add rsync's `--delete` option if you are running this multiple times to the same backup folder
Note: Consider also if you want to backup folder /home, if it contains your data, it might be considerably larger than the system.
Note: If you use any sparse files, such as Virtual disks, Docker images and other, you should add the `-S` `rsync` option.

## Using a script

Same as in the above method, the system files are transferred 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 `--exclude` string. On top of that, it shows at the end how much time it took, and it also writes a file stating when the backup was created. To learn more about what this script does, read `man rsync` and `man date`.

Note: Again, if you plan on backing up your system somewhere other than `/mnt` or `/media`, don't forget to add it to the list, to avoid an infinite loop.
Note: You may want to add rsync's `--delete` option if you are running this multiple times to the same backup folder

    ~/Scripts/backup.sh

    #!/bin/bash

    if [ $# -lt 1 ]; then
        echo "No destination defined. Usage: $0 destination" >&2
        exit 1
    elif [ $# -gt 1 ]; then
        echo "Too many arguments. Usage: $0 destination" >&2
        exit 1
    elif [ ! -d "$1" ]; then
       echo "Invalid path: $1" >&2
       exit 1
    elif [ ! -w "$1" ]; then
       echo "Directory not writable: $1" >&2
       exit 1
    fi

    case "$1" in
      "/mnt") ;;
      "/mnt/"*) ;;
      "/media") ;;
      "/media/"*) ;;
      "/run/media") ;;
      "/run/media/"*) ;;
      *) echo "Destination not allowed." >&2
         exit 1
         ;;
    esac

    START=$(date +%s)
    rsync -aAXv /* $1 --exclude={/dev/*,/proc/*,/sys/*,/tmp/*,/run/*,/mnt/*,/media/*,/lost+found,/var/lib/pacman/sync/*}
    FINISH=$(date +%s)
    echo "total time: $(( ($FINISH-$START) / 60 )) minutes, $(( ($FINISH-$START) % 60 )) seconds" | tee $1/"Backup from $(date '+%Y-%m-%d, %T, %A')"

Note: The contents of `/dev`, `/proc`, `/sys`, `/tmp`, `/run` were excluded because they are populated at boot (while the folders themselves are not created), `/lost+found` is filesystem-specific. For Arch Linux, `/var/lib/pacman/sync/*` can also be excluded. This can save a lot of time on every backup since the directory contains many small files that tend to change quite often. These are description files for every package from the repositories and can be re-generated with `pacman -Syu`.Also `/var/log/journal/*` may be skipped as it contains large number of systemd logs. Additionally, you may also want to skip `/home/*/.thumbnails/*`, `/home/*/.cache/mozilla/*` and `/home/*/.cache/chromium/*`, or even just all of `/home/*/.cache/*`.

Backing up is easy.

While the system is running, open up a terminal and run (as root):

    # /home/user/Scripts/backup.sh /some/destination

(replace user with username since you created the directory as user in the user's home directory)

You can also replace both `$1` instances from the script with the actual destination path, move it to one of the folders from `echo $PATH`, and then simply run (as root):

    # backup.sh

## Boot requirements

Having a bootable backup can be useful in case the filesystem becomes corrupt or if an update breaks the system. The backup can also be used as a test bed for updates, with the [testing] repo enabled, etc. If you transferred the system to a different partition or drive and you want to boot it, the process is as simple as updating the backup's `/etc/fstab` and your bootloader's configuration file.

### Update the fstab

Without rebooting, edit the backup's fstab to reflect the changes:

    /path/to/backup/etc/fstab

    tmpfs        /tmp          tmpfs     nodev,nosuid             0   0

    /dev/sda1    /boot         ext2      defaults                 0   2
    /dev/sda5    none          swap      defaults                 0   0
    /dev/sda6    /             ext4      defaults                 0   1
    /dev/sda7    /home         ext4      defaults                 0   2

Because rsync has performed a recursive copy of the entire root filesystem, all of the `sda` mountpoints are problematic and booting the backup will fail. In this example, all of the offending entries are replaced with a single one:

    /path/to/backup/etc/fstab

    tmpfs        /tmp          tmpfs     nodev,nosuid             0   0

    /dev/sdb1    /             ext4      defaults                 0   1

Remember to use the proper device name and filesystem type.

### Update the bootloader's configuration file

This section assumes that you backed up the system to another drive or partition, that your current bootloader is working fine, and that you want to boot from the backup as well.

For Syslinux, all you need to do is duplicate the current entry, except pointing to a different drive or partition.

Tip: Instead of editing `syslinux.cfg`, you can also temporarily edit the menu during boot. When the menu shows up, press the `Tab` key and change the relevant entries. Partitions are counted from one, drives are counted from zero.

For GRUB, it's recommended that you automatically re-generate the main configuration file.

Also verify the new menu entry in `/boot/grub/grub.cfg`. Make sure the UUID is matching the new partition, otherwise it could still boot the old system. Find the UUID of a partition as follows:

    # lsblk -no NAME,UUID /dev/sdb3

where you substitute the desired partition for /dev/sdb3. To list the UUID's of partitions grub thinks it can boot, use grep:

    # grep UUID= /boot/grub/grub.cfg

If the one you found from lsblk isn't found by grep, then grub-mkconfig didn't work. Most likely, you will have to Change Root into the duplicate file system and then use mkinitcpio. For example, if you had used rsync to duplicate root on /dev/sdb3 then change root and use mkinitcpio as follows:

    # mkdir /mnt/arch
    # mount /dev/sdb3 /mnt/arch
    # cd /mnt/arch
    # mount -t proc proc proc/
    # mount --rbind /sys sys/
    # mount --rbind /dev dev/
    # chroot /mnt/arch /bin/bash
    # mkinitcpio -p linux

After exiting, generate grub.cfg again and verify the new UUID is included.

## First boot

Reboot the computer and select the right entry in the bootloader. This will load the system for the first time. All peripherals should be detected and the empty folders in `/` will be populated.

Now you can re-edit `/etc/fstab` to add the previously removed partitions and mount points.

If you transferred the data from HDD to SSD (solid state drive), don't forget to activate TRIM. Also consider using HDD and tmpfs mount points to reduce SSD wearing - see Relocate files to tmpfs and Tips for Minimizing SSD Read & Writes.

Note: You may have to reboot again in order to get all services and daemons working correctly. Personally, pulseaudio would not initialise because of a module loading error. I restarted the dbus.service to make it work.

## See also

1. Howto – local and remote snapshot backup using rsync with hard links Includes file deduplication with hard-links, MD5 integrity signature, 'chattr' protection, filter rules, disk quota, retention policy with exponential distribution (backups rotation while saving more recent backups than older)

Category:

- System recovery