sub _replicate{
    my $ref = shift;
    
    foreach my $sc ( @{ $ref } ) {
        next unless (defined $sc);

        mkdir( $LOG_FOLDER . "/" . $sc->{sc_name} );
        my @thr_arr = ();

        foreach my $robj( @{ $sc->{ rsync} } ){
            $robj->{thr} => 'running';
           
            my $th = threads->create( \&worker, $robj );
            push @thr_arr, $th->tid;
        }
        $_->join for @thr_arr;
    }
}

sub worker{
    my $robj = shift;
    
    my( $rsync, $server, $from, $to ) = @{ $robj->{ elements } };
    my $alt_server = $RSYNC_CONN_STR_2;

    for my $i ( 0 .. $MAX_REPL_ATTEMPT ){
        my $rsync_cmd = $rsync . $server . $from . $to;
        
        `$rsync_cmd`;

        if ($?){ 
            $rsync_cmd = $rsync . $server . $from . $to;
            $server = ( $i % 2 ) ? $RSYNC_CONN_STR_1 : $RSYNC_CONN_STR_2; 
            sleep(120);
        }
        else{
            $robj->{status} = "Completed";
            last;
        }
    }
    $robj->{thr} = 'done';
}