DR servers need to shutdown for Hardware maintenance

Hi,

    We have a two node 10gR2 RAC production db on linux with  DR site having two physical standby databases on two standalone linux servers.

    In a couple of weeks, we have to shutdown two DR Linux standalone servers on which dbstandby1 and dbstandby2 db reside. They are in managed recovery mode constantly gets updated from primary RAC databases (db1 and db2). I am following the below steps to gracefully stop the DR servers:

On Primary db1

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1. alter system set log_archive_dest_state_2=defer scope = both sid = 'db1';

2. alter system switch logfile;  -- Do I need this PLEASE CLARIFY ??