In this tutorial, we'll learn about how to use rsync for file synchronization in Linux.
rsync is a powerful utility for efficiently transferring and synchronizing files across computer systems by checking the differences between source and destination files. rsync is a widely used utility for efficiently transferring and synchronizing files and directories between different locations, whether they are on the same machine, on different machines over a network, or between a local and remote system.
Key Features:
Incremental Transfers: rsync transfers only the parts of files that have changed, which reduces the amount of data sent over the network and speeds up synchronization processes.
Versatility: It supports local-to-local, local-to-remote, and remote-to-remote file transfers. For remote transfers, rsync can use SSH or RSH as the transport protocol.
Compression: It can compress data during transfer using the -z option, reducing the amount of data sent over the network.
Preservation of File Attributes: rsync can preserve file permissions, ownership, timestamps, and symbolic links, ensuring that the synchronized files retain their original properties.
Exclusion and Inclusion Rules: It allows fine-grained control over which files or directories to include or exclude from synchronization.
Efficient Synchronization: By comparing file checksums and timestamps, rsync ensures that only changed files or portions of files are transferred, optimizing the synchronization process.
Support for Daemon Mode: rsync can operate as a server, allowing for file synchronization over a network without needing SSH.
It stands out due to its ability to minimize data transfer by only sending differences between source and destination files, making it particularly effective for backups and mirroring. This tutorial covers the installation, configuration, and usage of rsync on Linux.
How to Use rsync or File Synchronization
Step 1: Install rsync
Most Linux distributions come with rsync pre-installed. You can check if it's already installed by running:
rsync --version
If rsync is not installed, you can install it using the package manager for your distribution.
On Debian-based systems (Ubuntu, etc.):
sudo apt update
sudo apt install rsync
On Red Hat-based systems (CentOS, AlmaLinux, etc.):
sudo dnf install rsync
Step 2: Basic rsync Usage
The basic syntax of rsync is:
rsync [options] source destination
Here are some common options:
-a : Archive mode; equivalent to -rlptgoD (recursive, preserve symlinks, permissions, timestamps, group, and owner).
-v : Verbose; shows the progress of the transfer.
-z : Compress file data during the transfer.
-h : Human-readable output.
--delete : Delete extraneous files from the destination directory.
Example 1: Synchronize a Local Directory
To synchronize files from the source directory (/source/directory/) to the destination directory (/destination/directory/):
rsync -avh /source/directory/ /destination/directory/
Example 2: Synchronize Files Over SSH
To synchronize files between a local and a remote system, use rsync over SSH:
rsync -avh -e ssh /source/directory/ user@remote_host:/destination/directory/
Step 3: Advanced rsync Usage
Synchronize in Both Directions
For bidirectional synchronization, use a tool like rsync with scripts or combine it with unison.
Exclude Files and Directories
To exclude certain files or directories, use the --exclude option:
rsync -avh --exclude 'file_or_directory_to_exclude' /source/directory/ /destination/directory/
Running rsync as a Cron Job
To automate rsync using cron, edit the crontab file:
crontab -e
Add a cron job entry, for example, to run rsync every day at 2 AM:
0 2 * * * rsync -avh /source/directory/ /destination/directory/
Step 4: Configuring rsync Daemon
To set up rsync as a daemon, follow these steps:
Edit the rsyncd.conf file:
Create or edit the /etc/rsyncd.conf file:
sudo nano /etc/rsyncd.conf
Add the following configuration:
[backup]
path = /path/to/directory
comment = Backup Directory
read only = no
uid = nobody
gid = nogroup
auth users = user
secrets file = /etc/rsyncd.secrets
Create the secrets file:
sudo nano /etc/rsyncd.secrets
Add the following:
user:password
Set the correct permissions for the secrets file:
sudo chmod 600 /etc/rsyncd.secrets
Start the rsync daemon:
sudo systemctl start rsync
sudo systemctl enable rsync
Connect to the rsync daemon:
rsync -avh /source/directory/ user@remote_host::backup
Conclusion
rsync is a versatile tool for file synchronization and transfer. By leveraging its various options and configurations, you can efficiently manage data between local and remote systems, automate backups, and ensure data consistency.
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