Andreas J. König > File-Rsync-Mirror-Recent > HOWTO.mirrorcpan


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As of this writing the single purpose for this distribution is to provide a fast rsync client/server combination for the CPAN.

You find a list of potential rsync servers at

Find current stats at

The first thing you should prepare is the CPAN tree itself on your disk. The source where you take it from does not matter that much. Take it from where you always took it.

The loop is something like this:

Short version:


    rrr-client --source rsync:// --target /home/rrrcpan/target --tmpdir /home/tmp &

Or if the short version is not sufficient for some reason, maybe you want only the authors/ and modules/ tree:

    use File::Rsync::Mirror::Recent;
    my @rrr = map {
                 localroot                  => "/home/rrrcpan/target/$_", # your local path
                 remote                     => "$_/RECENT.recent", # your upstream
                 max_files_per_connection   => 863, # arbitrary
                 tempdir                    => "/home/ftp/tmp", # optional tempdir to hide temporary files
                 ttl                        => 10,
                 rsync_options              =>
                  compress          => 1,
                  links             => 1,
                  times             => 1,
                  checksum          => 0,
                  'omit-dir-times'  => 1, # not available before rsync 3.0.3
                  timeout           => 300, # do not allow rsync to hang forever
                 tmpdir                     => "/home/rrrcpan/target",
                 verbose                    => 1,
                 verboselog                 => "/var/log/rmirror-pause.log",
                )} "authors", "modules";
    die "directory $_ doesn't exist, giving up" for grep { ! -d $_->localroot } @rrr;
    while (){
        my $ttgo = time + 1200; # arbitrary
        for my $rrr (@rrr){
            $rrr->rmirror ( "skip-deletes" => 1 );
        my $sleep = $ttgo - time;
        if ($sleep >= 1) {
            print STDERR "sleeping $sleep ... ";
            sleep $sleep;

Target directory is, of course, your choice, so replace '/home/rrrcpan/target' with your favorite path.

The tmpdir is important and must reside on the same partition as the target directory, so that rename(2) works.

You see the 'skip-deletes' and guess, this is mirroring without doing deletes. You can do it with deletes or you can leave the deletion to the other, the traditional rsync loop. Worry about that later.

You see the option 'max_files_per_connection' which I filled with 863 and you need to find your favorite number. The larger the number the faster the whole download goes. As you already have a mirror, you probably want to take 10 or 20 times times that much. CPAN's authors directory is at the moment (2010-10) consisting of 180000 files. This option chunks the downloads into piecemeal units and between these units the process takes a peek at the most recent files to download them with higher preference. That way we get the newest files immediately in sync while we are mirroring the long tail of old files.

The localroot parameter contains your target directory. Because only the authors/ and the modules/ directory are hosted by the PAUSE, you need the loop over two directories. The other directories of CPAN are currently not available for downloading with File::Rsync::Mirror::Recent.

The timeslice in the while loop above needs to be large enough to let the rsync server survive. If you choose a random rsync server and are not an rsync server yourself please be modest and choose 1200. Choose less if you're offering rsync yourself and have a fat pipe, and especially if you know your upstream can manage it.

Set the key 'verbose' to 0 if you have no debugging demands. In this case you want to omit the 'sleeping $sleep ...' noise further down the script as well.

Set the key 'verboselog' to your favorite progress watcher file. This option is underdeveloped and may later be replaced with something better. Note that the program still sends error messages to STDERR.

You can leave everything else as it stands. Start experimenting and let me know how it works out.

-- andreas koenig

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