Please use <c>...</c> tags around computer text (code, data, etc). To mark paragraphs, just start them with <p>.

I am almost certain that I have to make a hash with the server name as the key

Indeed. Hashes are great for grouping.

my %servers;
while (<>) {
    chomp;
    my ($server_id, @fields) = split /,/;
    my $server = $servers{$server_id} ||= [0, 0, 0];
    $server->[$_] += $fields[$_] for 0..$#fields;
}

for my $server_id (keys %servers) {
    my $server = $servers{$server_id};
    print(join(',', $server_id, @$server), "\n");
}
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Update: Fixed incorrect var names.