Introduction
rsync is a program that copies files from one location to another. With it you can make backups of your files, and synchronize data on different locations and computers. It is commonly used by unix users to keep a safe backup of their files and is often recommended as the simplest solution for backups and safety copys. Other software for backup is listed on BackupYourSystem.
Rsync minimizes data transfer using delta encoding when appropriate. This ability will minimize the amount of bandwidth used over the network. An important feature of rsync not found in most similar programs/protocols is that the mirroring takes place with only one transmission in each direction.
rsync
Installation
The program rsync is usually installed on Ubuntu. In the rare case when it is not on your system, install the following packages: rsync xinetd ssh.
Using rsync with SSH for a Simple Backup
Rsync is especially good for backing up home directories. For safety, transfer between two machines is done via SSH. Also, SSH is installed on most unix machines, so this method will be easier for you to use.
The command for transferring to a remote machine is:
sudo rsync --delete -azvv -e ssh /home remoteuser@remotehost.remotedomain:/home/Backup
In the above example:
--delete deletes files that don't exist on the system being backed up.(Optional)
-a preserves the date and times, and permissions of the files (same as -rlptgoD).
- With this option rsync will:
Descend recursively into all directories (-r),
copy symlinks as symlinks (-l),
preserve file permissions (-p),
preserve modification times (-t),
preserve groups (-g),
preserve file ownership (-o), and
preserve devices as devices (-D).
-z compresses the data
-vv increases the verbosity of the reporting process
/home Is the directory on the local (current) machine to be backed up. In this case, /home directory and everything recursively below it.
/home/Backup Is the directory on the remote machine where the backup is made. In this case, a folder called Backup under /home.
A complete synopsis of all the options with the rsync command can be found in the man pages under "Options Summary". The man page for rsync can also be found on linux.die.net
rsync has several graphical frontends: grsync, Backup Monitor, QSync, Zynk, rsyncbackup, TKsync A guide to grsync is below.
Configuration of the rsync Daemon
You need the rsync daemon when you want to synchronize two computers and the simple way using SSH doesn't work for you. Using the daemon is usually more complicated than just using rsync with an ssh connection.
1. Edit the file /etc/default/rsync to start rsync as daemon using xinetd. The entry listed below, should be changed from false to inetd.
RSYNC_ENABLE=inetd
2. Create the file /etc/xinetd.d/rsync to launch rsync via xinetd. It should contain the following lines of text.
service rsync
{
disable = no
socket_type = stream
wait = no
user = root
server = /usr/bin/rsync
server_args = --daemon
log_on_failure += USERID
}3. Create the file /etc/rsyncd.conf configuration for rsync in daemon mode. The file should contain the following. In the file, user should be replaced with the name of user on the remote machine being logged into.
max connections = 2 log file = /var/log/rsync.log timeout = 300 [share] comment = Public Share path = /home/share read only = no list = yes uid = nobody gid = nogroup auth users = user secrets file = /etc/rsyncd.secrets
4. Create /etc/rsyncd.secrets for user's password. User should be the same as above, with password the one used to log into the remote machine as the indicated user.
$ sudo vim /etc/rsyncd.secrets user:password
5. This step sets the file permissions for rsyncd.secrets.
$ sudo chmod 600 /etc/rsyncd.secrets
6. Start/Restart xinetd
$ sudo /etc/init.d/xinetd restart
Testing
Run the following command to check if everything is ok. Hostname can be replaced by the IP address of the machine.
$ sudo rsync user@hostname::share Password: drwxr-xr-x 4096 2006/12/13 09:41:59 . drwxr-xr-x 4096 2006/11/23 18:00:03 folders
grsync
The program grsync is a GUI front for rsync. The simple interface of the GUI exposes many of the basic options usable with rsync and is useful for those not wishing to use the command line.
Installation
The program grsync does not come installed by default on Ubuntu or any other distrubtion but it is easily available from the main Repositories. To get grsync ensure Universe section of the Ubuntu repositories is enabled in your Software Sources. Then to install this software in Ubuntu, install the following package: grsync.
Configuration
To start up grsync go through the following menus: Applications --> System Tools --> grsync. Upon start up you'll be presented with the main window, where all the configuration takes place.
On this window are all of the options most users will ever need. To explain, the options will be listed and their effects mentioned.
Sessions - This function is the same as profiles in others. Each session will store a different set of source and destination directories, as well as the configuration options associated with the folder pair. This allows for the synchronization of different sets of folders according to different options.
Management of sessions is simple, simply push the Add button to add a new one. To delete, select the session you no longer want from the drop down and push Delete.
Source and Destination - These two boxes list the two folders (technically referred to as directories) that will be synchronized. The top one is the Source and the bottom the Destination. So when you Execute the synchronization, the files from Source will be copied over to the Destination according to the options a user selects.
To specify the directories either Browse for them from the GUI or type them in according to the standard path conventions.
Switch - The universal reload sign located to the right of the Browse buttons is a handy button. It will instantly switch the Source with the Destination.
Import and Export - After having configured sessions, a user may want to back them up for storage. To do so, simply go to the Sessions Menu at the top and select either Import or Export. The former will restore a session from a backup previously made, the latter will make a backup of the current session.
Note: This backup function works on a per session basis. This means, each session you want to back up must be selected from the drop down and then backed up. If you have 3 different sessions, select each in turn and Export them. Same when importing sessions.
Basic Options - Most users will find most of the options they will ever need here. The first four will preserve the properties of the files transferred. The others will modify how the files are copied. For more information on what each does specifically, hover your stationary cursor over the option and it will display a small explanation. The options checked are of course the ones that will be applied during the session.
Advanced Options - This tab holds more options, many are useful and self-explanitory. For those not understood, tooltips will be displayed when the mouse remains over an option long enough.
Additional Options - This entry box allows the input of additional options not presented in the GUI but known to the user. Use is suggested only for experienced users, inputting malformed options may have unexpected consequences.
Simulation and Execution
The last two buttons on the window are Simulation and Execute. The button for simulation is very useful when uncertain what will happen based on the options selected. The normal transfer dialog screen will pop up and in the main pane, a list of files that would have been copied over is listed. The user can then verify if this is as desired or make changes. Once the session is initiated with the Execute button, the dialog will appear again but this time it will actually process the folders accordingly. Ensure before pushing Execute that you are happy with the simulation.
Remote Backup
Backup over a network is possible, preferably the user should mount the network share to be backed up to prior to launching the program. The share would then be listed in the Browse GUI and could easily be added. There is no separate section for network, if more advanced features are required the user is encouraged to look at alternatives, of which there are many.
Alternatives
There are many alternatives, in various stages of development. For an incomplete list, see here.