apt-metalink makes apt-get faster by downloading Debian/Ubuntu packages from several servers concurrently. apt-metalink uses python3-apt to interface apt infrastructure and aria2 for download backend. Metalink is used to feed package list to aria2.
If multiple debian mirror is specified in /etc/apt/sources.list, packages are usually available in more than one server. apt-get only uses 1 URI to download package in sequential manner. apt-metalink uses the advantage of availability of these mirrors. apt-metalink establishes 1 connection per mirror and downloads packages from all mirrors in sources.list. This is as if running apt-get with different mirror and mutually exclusive subset of packages at the same time. This parallelism shortens whole download time. The difference of parallel transfer and sequential transfer gets bigger when the number of packages to download increases. The connection to the remote server is reused across the download, so it is very efficient.
apt-metalink uses aria2 as download backend. You can install aria2 with following command:
apt-get install aria2
I strongly recommend to use the latest release of aria2. You can download aria2 from https://aria2.github.io/
apt-metalink also depends on python3-apt package. You can install python-apt with following command:
apt-get install python3-apt
But I think it is usually already in your system. If you see that apt-metalink reports there are packages to update but the total size is 0 byte, then it is a sign that python3-apt needs to be updated. Please update python3-apt first in this case.
sources.list is ususally located at /etc/apt/sources.list. Add several fast debian mirror server to it. Don’t add slow mirror. It voids the power of apt-metalink. For example, adding 3 debian mirror:
deb http://MIRROR1/debian/ unstable main contrib non-free deb http://MIRROR2/debian/ unstable main contrib non-free deb http://MIRROR3/debian/ unstable main contrib non-free
See sources.list(5) for more details.
apt-metalink uses them all and download packages concurrently, which makes download faster.
Currently, apt-metalink passes the number of mirrors as -j option to aria2c.
Usage: apt-metalink [options] {upgrade | dist-upgrade | install pkg ...}
Options:
-h, --help show this help message and exit
-d, --download-only Download only. [default: False]
--print-metalink Instead of fetching the files, Metalink XML document
is printed. Metalink XML document contains package's
URIs and checksums.
--hash-check Check hash of already downloaded files. If hash check
fails, download file again.
-x ARIA2C, --aria2c=ARIA2C
path to aria2c executable [default: /usr/bin/aria2c]
Currently, apt-metalink offers very basic subset of features that apt-get has: upgrade, dist-upgrade and install. But I think this is enough to see what apt-metalink offers and its possibility.
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https://tools.ietf.org/html/rfc5854 The Metalink Download Description Format
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https://aria2.github.io/ aria2 project