Full system backup with rsync
Related articles
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 will not get the same opened tabs when you restore the backup (or boot from it) because they were not saved. Not a big deal.
Contents
With a single command
This command depends on brace expansion available in both the bash and zsh shells. When using a different shell, --exclude
patterns should be repeated manually.
# rsync -aAXv --exclude={"/dev/*","/proc/*","/sys/*","/tmp/*","/run/*","/mnt/*","/media/*","/lost+found"} /* /path/to/backup/folder
Using the -aAX
set of options, the files are transferred in archive mode, ensuring that symbolic links, devices, permissions and ownerships, modification times, ACLs and extended attributes are preserved.
The --exclude
option will cause files that match the given patterns to be excluded. The contents of /dev
, /proc
, /sys
, /tmp
and /run
were excluded because they are populated at boot (while the folders themselves are not created), /lost+found
is filesystem-specific. Quoting the exclude patterns will avoid expansion by shell, which is necessary e.g. when backing up over SSH.
You may want to include additional rsync options, such as the following (see man rsync
for the full list):
- If you are a heavy user of hardlinks, you might consider adding the
-H
option, which is turned off by default as memory expensive, but nowadays it should be no problem on most modern machines. There are a lot of hard links below the/usr/
folder, which save disk space. - You may want to add rsync's
--delete
option if you are running this multiple times to the same backup folder. - If you use any sparse files, such as virtual disks, Docker images and similar, you should add the
-S
option. - The
--numeric-ids
option will disable mapping of user and group names, numeric group and user IDs will be transfered instead. This is useful when backing up over SSH or when using a live system to backup different system disk. - Choosing
--info=progress2
option instead of-v
will show overal progress info and transfer speed instead of huge list of files.
Automated
See Backup programs#Rsync-type backups.
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.
For GRUB, it is 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 UUIDs of partitions grub thinks it can boot, use grep:
# grep UUID= /boot/grub/grub.cfg
If the one you found from lsblk is not found by grep, then grub-mkconfig did not 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), do not 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.
See also
- 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)