This software allows synchronization of files between computers or servers over HTTP protocol, using the widely used rsync algorithm.
Zsync is a reliable file transfer program that enables you to download a file from a remote server, if you already have an older version of the file on your computer. The program is designed to download only the new parts of the file, using the same algorithm as rsync. Unlike rsync, which is ideal for synchronizing data within an organisation, zsync is meant for large scale file distribution, with one file on a server to be distributed to thousands of downloaders.
Zsync requires no special server software, other than a web server to host the files, and doesn't impose any extra load on the server, making it perfect for large scale file distribution. The program is open source, distributed under version 2 of the Artistic License, and feedback, bug reports, and patches are welcome.
Zsync fills a gap in the technology available for large-scale file distribution, offering a genuinely new technique for file distribution with three key points that differentiate it from other file transfer programs. Firstly, it uses client-side rsync, which avoids the high server load associated with rsync. Secondly, it provides transfers that are nearly as efficient as rsync without requiring a special server application. Lastly, it has special handling for gzipped files that enables update transfers of files that are distributed in compressed form.
The combination of client-side rsync and HTTP is unique to zsync, and the program has made a deliberate effort to make zsync simple, reliable, and easy to deploy. Zsync downloads are offered by building a .zsync file that contains the meta-data needed by zsync. The file contains the precalculated checksums for the rsync algorithm, and it is generated on the server, once, and is then used by any number of downloaders. The .zsync files have a simple text header, so they can be edited with any good editor to change details like the download URL.
The .zsync file contains either a relative URL to the full content of the file or one or more absolute URLs, meaning the .zsync can be hosted on a different server entirely. Because zsync is a file distribution method, it is useful only when people offer .zsyncs for downloads. However, to help build up a user base, some zsync downloads are available on the client page. If you are a server operator looking to use zsync for file distribution, see the server page, which gives some guidance on how to create and offer .zsync files.
Zsync requires no special server software, other than a web server to host the files, and doesn't impose any extra load on the server, making it perfect for large scale file distribution. The program is open source, distributed under version 2 of the Artistic License, and feedback, bug reports, and patches are welcome.
Zsync fills a gap in the technology available for large-scale file distribution, offering a genuinely new technique for file distribution with three key points that differentiate it from other file transfer programs. Firstly, it uses client-side rsync, which avoids the high server load associated with rsync. Secondly, it provides transfers that are nearly as efficient as rsync without requiring a special server application. Lastly, it has special handling for gzipped files that enables update transfers of files that are distributed in compressed form.
The combination of client-side rsync and HTTP is unique to zsync, and the program has made a deliberate effort to make zsync simple, reliable, and easy to deploy. Zsync downloads are offered by building a .zsync file that contains the meta-data needed by zsync. The file contains the precalculated checksums for the rsync algorithm, and it is generated on the server, once, and is then used by any number of downloaders. The .zsync files have a simple text header, so they can be edited with any good editor to change details like the download URL.
The .zsync file contains either a relative URL to the full content of the file or one or more absolute URLs, meaning the .zsync can be hosted on a different server entirely. Because zsync is a file distribution method, it is useful only when people offer .zsyncs for downloads. However, to help build up a user base, some zsync downloads are available on the client page. If you are a server operator looking to use zsync for file distribution, see the server page, which gives some guidance on how to create and offer .zsync files.
What's New
Version 0.6.1: N/A