Then came Oracle 11g with the “active standby database” feature (sometimes referenced as real-time query).

With this feature we can open the database in “read only” mode, and can still apply archive logs from the primary.

Let’s see how it works…

Physical standby database is a common solution for DR. We can maintain it automatically using Data Guard, or manually by copying archived redo logs to the standby server and apply them to the database.

However, before using the standby database we need to create it. Usually we backup the primary database, copy the backup files to the standby server and restore the database. But there is another way, we can duplicate the primary directly to the standby server without the need for disk space and copying files.

Let’s see how that works….