You can start database replication while the master database,
    the standby database, or both databases are on line (open) and
    accessible for active use. There is no need to close either
    database to initiate database replication.

    Applications and users can continue to access data and make
    modifications to the master database whether or not replication
    activity has started. Waiting for the replication activity to
    begin does not inhibit access to, or interrupt modifications on,
    the master database.

    Starting replication is an online operation that can occur while
    the standby database is open. However, database users must
    not actively attach to the standby database prior to starting
    database replication if you perform offline backup operations.

    Replication operations cannot start when these conditions exist:

    o  Any read/write transactions, including prestarted read/write
       transactions, are active on the standby database

    o  Any read-only (snapshot) transactions are running on the
       standby database. The Log Rollforward Server waits until the
       read-only transactions commit.

    o  The row cache feature cannot be active on the standby
       database.

       The row cache feature must be identically configured on the
       master and standby databases in the event failover occurs,
       but the row cache feature must not be activated on the standby
       database until it becomes the master.

       To open the hot standby database prior to starting
       replication, use the NoRow_Cache qualifier on the RMU Open
       command to disable the row cache feature.

    o  Any storage area is inconsistent (for example, if you restore
       a storage area from a backup file but you have not rolled
       forward after-image journals to be consistent with the rest of
       the database)

                                   NOTE

       On OpenVMS systems, if you have preconfigured your Hot
       Standby environment using the Replicate After_Journal
       Configure command and you plan to start replication
       operations remotely (for example, if you want to start
       replication on the standby database from the master
       database node), you must provide the SYSPRV privilege to
       the DBMAIJSERVER or RDMAIJSERVER account.