It may be desirable to maintain a copy of your database on another machine in standby mode. You can quickly and easily make a standby copy of a database by restoring and recovering a backup on another machine.
As transaction journals become archived (or offline) on your primary system, you can then copy them to the standby system, verify them, and apply them to the database.
When a transaction journal switch occurs, a journal switch control record is written to the end of the journal. When this record is processed by roll‑forward recovery and it is the final record in the transaction journal, the recovery process knows that later transaction journals can exist so the database state is maintained such that a further roll‑forward recovery from that point is possible.
When the batch JADE Database utility (jdbutilb) is run to recover the database, it processes the next journal and whatever in‑order later journals exist in the directory.
The interactive JADE Database utility (jdbutil) processes journals in the same manner except that if a journal switch control record is found at the end of the last journal in the directory, it waits for the next journal file to be provided or for the user to finish or abort the recovery processing.
Both versions of the JADE Database utility support continuing roll‑forward recovery over multiple process executions. Any other open of the database cancels the preserved state that enables continuous roll‑forward recovery.
While warm standby servers can provide adequate functionality, a fully automated and capability‑rich standby server implementation is available with the Synchronized Database Service, described in the next section.
Because of byte ordering or operating system differences, the format of physical database files differs between hardware architectures and/or operating systems. You therefore cannot interchange database files directly by backing up a database on one machine and then restoring the database on a machine with a different operating system or hardware byte order.