You could change the distribution of @mirrors like this

my @mirrors;

push @mirrors, 'http://foo.mirror.org'                   for 1..3;
push @mirrors, 'http://www.users-domain.com/proj/foo'    for 1..2;
push @mirrors, 'http://osdn.dl.sf.net/sourceforge/foo'   for 1..3;
push @mirrors, 'http://unc.dl.sf.net/sourceforge/foo'    for 1..4;
push @mirrors, 'http://umn.dl.sf.net/sourceforge/foo'    for 1..4;
push @mirrors, 'http://heanet.dl.sf.net/sourceforge/foo' for 1..5;
push @mirrors, 'http://aleron.dl.sf.net/sourceforge/foo' for 1..5;

print $cgi->a({-href  =>
       "$mirrors[int(rand(@mirrors))]/$file-$stable.rpm",
               -title =>"$stable RPM"}, 'rpm');
[download]

Rather than duplicating the array entries, I'd duplicate the indexes.

my $pick = ( 
    (0)x3, 
    (1)x4, 
    (2)x4, 
    (3)x5, 
    (4)x6, 
    (5)x6, 
    (6)x6, 
    (7)x6 
)[ rand 40 ];

print $cgi->a({-href  =>
       "$mirrors[ $pick ]/$file-$stable.rpm",
               -title =>"$stable RPM"}, 'rpm');
[download]

This uses less memory but introduces a more difficult synchronisation task when mirrors are changed.

 

Actually, it probably doesn't save any memory either.

The size of a scalar has a minimum overhead. Anything below about 20 characters (guess) in length requires the same amount of memory, so the fact that the integers appear smaller than the string will have negligable savings.

Worse, doing it my way requires a (short lived) second array (list) to be built, which will consume almost as much memory as the original array, thereby doubling the consumption breifly.

Overall, your method is probably better for the reasons of simplified maintanence. The only change I would make to yours is that I would use the x operator in the initialisation rather than iterated pushes.

my @mirrors     = (
    ('http://foo.mirror.org') x 3,
    ('http://www.users-domain.com/proj/foo') x 2,
    ('http://osdn.dl.sf.net/sourceforge/foo') x 3,
    ('http://unc.dl.sf.net/sourceforge/foo') x 4,
    ('http://umn.dl.sf.net/sourceforge/foo') x 4,
    ('http://heanet.dl.sf.net/sourceforge/foo') x 5,
    ('http://aleron.dl.sf.net/sourceforge/foo') x 5,
);
[download]

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"Efficiency is intelligent laziness." -David Dunham
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