RSYNC, sometimes referred to as remote sync, is an open source command-line tool for Unix and Unix-like systems that provides fast incremental file transfer. It is commonly found in distribution such as Linux, BSD, and macOS. The first release was in 1996 by Andrew Tridgell and Paul Mackerras.
RSYNC is especially useful for synchronizing files and directories from one location to another while minimizing data transfer cost by using delta encoding when appropriate. An important feature of RSYNC, not found in most similar programs, is that the mirroring takes place with only one transmission in each direction which allows it to synchronize files between machines on a local network as well as machines on different networks connected through the internet.
RSYNC accomplishes its task by sending the differences between the source files and the existing files in the destination, rather than sending the full file. It uses a specific algorithm that minimizes the amount of data sent over the network by only transmitting the differences between the source and destination files. If the destination file is up to date, no data is transferred which makes RSYNC particularly efficient.
For example, if you were backing up a large database file everyday using traditional copy methods, each backup would require transferring the entire database file to the backup location. However, with RSYNC, only the changes made to the database file each day would need to be sent to the backup location, significantly reducing the amount of data transferred.
Furthermore, RSYNC can also maintain the full directory structure, permissions, time stamps, and ownership of files, even when transferring between different file systems and operating systems.
Therefore, RSYNC is most commonly used for backup and mirroring purposes. For instance, if a company has multiple office locations, it may need to mirror a collection of files from the primary server to a backup server located elsewhere. These files could be website files, critical documents, system configuration files, or other important data, and it can preserve all characteristics such as permissions and timestamps, ensuring a precise copy at the remote location.
In conclusion, RSYNC is an extremely powerful tool owing to its versatility and efficiency in file transfers, particularly in sync and backup operations. Its intelligent mechanism for transferring only the differential data between source and target files optimally utilizes bandwidth, making it a favorite in the repertoire of system administrators and end-users.
The information is derived from these sources:
Tridgell, Andrew (1998); Mackerras, Paul. Efficient Algorithms for Sorting and Synchronization
“How to Use Rsync for Local and Remote Data Transfer and Synchronization”. Linux.com.
“rsync”. manpages.ubuntu.com.
