backup.pl

    my $innodb_data_file_path = 
        get_option(\%config, $option_defaults_group, 'innodb_data_file_path');

    # run ibbackup as a child process
    $cmdline = "$option_ibbackup_binary $options";

    # Only use --rebuild-indexes in the first xtrabackup call
    $cmdline_copy = $cmdline;
    if ($option_rebuild_indexes) {
        $cmdline = $cmdline . " --rebuild-indexes"
    }
    if ($option_rebuild_threads) {
        $cmdline = $cmdline . " --rebuild-threads=$option_rebuild_threads"
    }

    $now = current_time();
    print STDERR "\n$now  $prefix Starting ibbackup with command: $cmdline\n\n";
    $rcode = system("$cmdline");
    if ($rcode) {
        # failure
        die "\n$prefix ibbackup failed";
    }