#!/usr/bin/perl
use strict;
use warnings;
my @data;
while ( <DATA> ) {
    next if /^host:volume/;
    chomp;
    my @field = $_ =~ /^([^:]+):([^\s]+)\s+(\d+)\s+(\d+)/;
    push @data, \@field;
}

for ( sort { $data[$a]->[2] <=> $data[$b]->[2] } 0 .. $#data ) {
    print join "\t" , @{ $data[$_] };
    print "\n";
}
__DATA__
host:volume              available(MB)   %free
10.100.200.1:/dev/hda3        10168   80%
10.100.200.1:/dev/hda2        84      90%
10.100.200.2:/dev/hda3        10168   80%
10.100.200.2:/dev/hda2        84      90%