Difference between revisions of "Full system backup with rsync (正體中文)"

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=== 更新 fstab ===
=== 更新 fstab ===
Without rebooting, edit the backup's [[fstab]] to reflect the changes:
在重開機之前你必須先修改備份後的系統的 [[fstab]] 來讓它能夠讀取到變更後的磁區:
{{hc|# nano /path/to/backup/etc/fstab|2=
{{hc|# nano /path/to/backup/etc/fstab|2=
tmpfs        /tmp          tmpfs    nodev,nosuid            0  0
tmpfs        /tmp          tmpfs    nodev,nosuid            0  0
Line 93: Line 93:
/dev/sda7    /home        ext4      defaults                0  2</i></font>}}
/dev/sda7    /home        ext4      defaults                0  2</i></font>}}
Because rsync has performed a recursive copy of the ''entire'' root filesystem, all of the {{ic|sda}} mountpoints are problematic and booting the backup will fail. In this example, all of the offending entries are replaced with a single one:
因為 rsync 將整個磁碟都備份過來,所以所有原本的 {ic|sda}} 掛載點,在重開機後就會出錯,所以我們必須將掛載點更改成新的裝置,像是把 sda 更改成 sdb:
{{hc|# nano /path/to/backup/etc/fstab|
{{hc|# nano /path/to/backup/etc/fstab|
Line 100: Line 100:
/dev/'''sdb1'''    /            ext4      defaults                0  1}}
/dev/'''sdb1'''    /            ext4      defaults                0  1}}
Remember to use the proper device name and filesystem type.
=== 更新 bootloader 的設定檔 ===
=== 更新 bootloader 的設定檔 ===

Revision as of 03:46, 4 February 2014

這篇文章是教你使用 rsync 來備份你的 "/" , 並且排除部份目錄。 這個方法比使用 dd 備份磁碟 更好。我們可以使用這個方法備份不同的磁區大小以及不同的檔案系統,而且這個方法也比使用 cp -a 來得更好,因為有更好的的檔案權限控管,以及保留檔案屬性還有 Access Control Lists (ACLs). [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.


使用 root 權限, 執行:

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


Note: 如果你是重度使用 hardlinks 的使用者,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

使用 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 blank 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
$ cd ~/Scripts
$ nano backup.sh

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

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

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 '+%A, %d %B %Y, %T')"
$ chmod +x backup.sh
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/*/.mozilla/firefox/*.default/Cache/* and /home/*/.cache/chromium/*.

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


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.

更新 fstab

在重開機之前你必須先修改備份後的系統的 fstab 來讓它能夠讀取到變更後的磁區:

# nano /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

因為 rsync 將整個磁碟都備份過來,所以所有原本的 {ic|sda}} 掛載點,在重開機後就會出錯,所以我們必須將掛載點更改成新的裝置,像是把 sda 更改成 sdb:

# nano /path/to/backup/etc/fstab
tmpfs        /tmp          tmpfs     nodev,nosuid             0   0

/dev/sdb1    /             ext4      defaults                 0   1


更新 bootloader 的設定檔

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.
# nano /boot/syslinux/syslinux.cfg

For GRUB, it's recommended that you automatically re-generate the grub.cfg file:

# pacman -S os-prober
# grub-mkconfig -o /boot/grub/grub.cfg

Also verify the new menu entry in /boot/grub/grub.cfg. Make sure the UUID is matching the good partition, or else it could still boot on the old system.


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.


  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)