TL;DR
The OpenBSD project has integrated openrsync, an open-source implementation of the rsync protocol, into its system. This development enhances compatibility and offers a BSD-licensed alternative to the traditional rsync tool.
The OpenBSD project has merged openrsync, an implementation of the rsync protocol licensed under BSD (ISC), into its base system, making it available for use and development within OpenBSD. This move provides an open-source alternative to the traditional rsync tool, with compatibility for recent protocol versions and a focus on portability and licensing clarity.
Openrsync is a reimplementation of the widely used rsync utility, originally developed by the OpenBSD team. It supports a subset of rsync’s command-line arguments but is compatible with protocol 27, used by rsync version 3.1.3, and potentially newer versions. The project was funded by organizations including NetNod, IIS.SE, SUNET, and 6connect, and is designed to be portable across UNIX systems, though officially supported on OpenBSD.
The implementation is part of the rpki-client project, an RPKI validator, and can be installed on UNIX systems by downloading, configuring, and compiling the source code. It can run alongside existing rsync installations without conflict. The source code and manual pages are publicly available, and contributions are encouraged via mailing patches to the OpenBSD team.
Openrsync’s architecture follows the standard rsync algorithm, involving a sender and receiver that share file lists and metadata, then perform block-based synchronization using hashing algorithms like Adler-32 and MD4. The process involves generating file lists, sorting them, and exchanging blocks of data to update files efficiently. The implementation handles directories, symbolic links, and regular files differently, optimizing for minimal data transfer.
Why It Matters
This development matters because it provides an open-source, BSD-licensed implementation of the rsync protocol, which is widely used for remote file synchronization. It offers OpenBSD users and developers a more transparent, customizable, and potentially more secure alternative to the proprietary or closed-source versions of rsync. Additionally, it facilitates integration into systems where licensing restrictions or open-source policies are critical, and supports ongoing development and experimentation within the open-source community.
rsync alternative open-source software
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Background
The rsync protocol was originally developed by Andrew Tridgell and Paul Mackerras, with the algorithm detailed in Tridgell’s PhD thesis. Historically, rsync has been a key tool for efficient file transfer and backup in UNIX environments. The OpenBSD team has maintained its own version, and now with openrsync merged into the base system, the project aims to improve transparency and community involvement. Prior to this, users relied on the official rsync tool, which is under the GPL license, whereas openrsync is BSD-licensed, aligning with OpenBSD’s licensing philosophy.
“Integrating openrsync into the base system reflects our commitment to open-source principles and provides users with a BSD-licensed alternative to the traditional rsync.”
— OpenBSD project spokesperson
“Openrsync is compatible with modern rsync protocols and can be used alongside existing tools, offering flexibility and transparency.”
— OpenBSD developer
BSD licensed file synchronization tool
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What Remains Unclear
It is not yet clear how widely openrsync will be adopted by the OpenBSD community or whether future updates will expand its feature set to match the full capabilities of the official rsync tool. Details about ongoing development, support for newer protocols, and integration with other system components remain to be seen.
UNIX system file transfer utility
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What’s Next
Next steps include community testing, potential contributions to enhance functionality, and monitoring how openrsync is adopted within OpenBSD deployments. The project team may also work on extending protocol support and improving documentation.
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Key Questions
What is openrsync and how does it differ from the standard rsync?
Openrsync is an open-source implementation of the rsync protocol, licensed under BSD (ISC). It supports a subset of rsync’s features but is compatible with recent protocol versions and designed for portability and transparency.
Is openrsync fully compatible with existing rsync tools?
It is compatible with protocol 27 (used by rsync 3.1.3) and can work alongside existing rsync installations, but it supports only a subset of command-line options and features.
Can I use openrsync on systems other than OpenBSD?
Yes, openrsync can compile and run on other UNIX systems, though it is officially supported only on OpenBSD. Its portability allows broader use, but some features may vary.
What are the benefits of using openrsync instead of the official rsync?
Openrsync offers a BSD-licensed, open-source alternative, providing transparency, potential security benefits, and the ability to modify and extend the code for specific needs.
Source: Hacker News
