Use Metalink to assist in ISO downloads

Registered by Ant Bryan on 2007-02-26

Metalink can help with ISO downloads.
Wubi, the Windows Ubuntu Installer, uses Metalink via Metadl to download ISOs. Numerous other Linux/BSD distributions, OpenOffice.org, and cURL make use of it. It is a file format and system supported by download programs.
Metalink has the following advantages:
* List multiple FTP/HTTP/P2P sources for a download. A .metalink for an ISO will list all mirrors that it is available from. (This allows for faster downloading with segmented multi-source downloads, if you want).
* Some ISPs and organizations don't allow P2P, so it's good to have the FTP/HTTP sources.
* Some users have trouble with P2P downloads because of configuration issues.
* If one link or server fails, download automatically continues using another.
* Automatic full file checksum verification at end of transfer.
* Automatic error correction for downloads in progress and repairing of corrupted downloads (using optional chunk checksums/repair info/segment hashes).
* Ability to give certain mirrors or P2P sources priority.
* List location information (by country) for mirrors, so downloads can be filtered by location.
* Simplifies download page layout (which currently contain many pages of redundant mirror lists).
* No server side changes or tracker necessary.
* GPLed Clients for Mac, Unix, and Windows, along with non-Free clients. (aria2 included in feisty).

People have been using Metalinks to download Ubuntu, Edubuntu, and Kubuntu ISOs for almost a year from http://download.packages.ro/metalink/ (There are multiple GPL programs for Metalink generation).

The Metalink project is interested in all changes and improvements that anyone might recommend.

More information:
* http://www.metalinker.org/
* http://en.wikipedia.org/wiki/Metalink
* Another proposal for Metalink system wide: https://blueprints.launchpad.net/ubuntu/+spec/metalink
* Another proposal for Metalink for ISO downloads: https://blueprints.launchpad.net/ubuntu-cdimage/+spec/segmented-downloading

Blueprint information

Status:
Complete
Approver:
None
Priority:
Low
Drafter:
Ant Bryan
Direction:
Needs approval
Assignee:
Ant Bryan
Definition:
Approved
Series goal:
None
Implementation:
Implemented
Milestone target:
None
Started by
Ant Bryan on 2007-02-26
Completed by
Ant Bryan on 2008-05-08

Whiteboard

2007-11-02 This feature is pretty much a requirement for Wubi, https://blueprints.launchpad.net/ubuntu/+spec/installer-for-windows

Sessions at UDS Boston didn't happen because of co-scheduling and people not showing up. Format could really do with a $prefix ... $postfix macro system to allow specifying a set of mirror and a set of files, rather than a full matrix of all combinations. - sladen

2007-11-02 - I do not agree with sladen. Metalink has no direct relation with Wubi. Metalink is a way os distributing Ubuntu ISO with more bandwithd, summing up all mirrors and torrents connections to provide more speed to everyone, mainly in the first week of a release. Metalink is a better mirroring system, not a installing system. Please, read more about it. - KurtKraut

2008-05-08 Official .metalinks are at http://releases.ubuntu.com/8.04/ and other places. These are used by Wubi, but not seen from the main download page.

2007-11-02 Metalink is very useful per se, with or without Wubi. Wubi is only an additional argument in favor of this blueprint. The blueprint has been discussed separately and there was general agreement that a script should be used in the ISO building mechanism to generate the metalink files, which in turn should be made available on the Ubuntu website. - AgostinoRusso

(?)

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