unrelated to the Unix pack command, it can have the same effect, which matters if resources lack:

use Devel::Size qw(total_size);

my @aoa = map { [ int rand 1_000_000, int rand 20_000, chr 32 + int ra
+nd 40 ] } 0 .. 450_000;
my @aop = map { pack "l>s>A", @$_ } @aoa;

say "Unpacked: ", total_size (\@aoa);
say "Packed:   ", total_size (\@aop);

=>

$ perl test.pl
Unpacked: 100800288
Packed:   28800128
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