Performing Oracle User-Managed Backups - OCP: Oracle Database 12c Administrator Certified Professional - page 18

The archived redo logs may be copied to one or a number of different destinations. We
will discuss configuring where Oracle should copy these archived redo logs to in the section
“Configuring the Database for Backup and Recovery.”
We will discuss how to back up your database in ARCHIVELOG mode later in this
chapter. In Chapter 2 we will discuss recovering your database with backups taken in
ARCHIVELOG mode. In Chapter 3 we will discuss using RMAN to perform online
backups, and in Chapter 5 we will discuss using RMAN to restore these backups. Finally,
in Chapter 7, “Performing Oracle Advanced Recovery,” we will discuss more-advanced
recoveries with backups taken in ARCHIVELOG mode.
The Oracle Instance and the Oracle Database
In the following sections, we will first review knowledge you should already have on the
basics of the Oracle instances and the Oracle Database. Then we will discuss the startup
and shutdown of the Oracle instance and the Oracle Database.
Oracle Instances and Oracle Databases: a Review
With respect to backup and recovery of Oracle databases, it is important to understand that
there is a difference between an Oracle instance and an Oracle database. This is because
certain backup and recovery operations must occur while the Oracle instance is running
and the database is not. Other operations will require that the database be open (which
presumes the instance is already running).
No doubt you are already somewhat familiar with the notion of the instance from your
OCA experience as well as your actual database experience. To review, an Oracle instance
is the collection of shared memory (SGA) and processes (LGWR, DBWR, and so on). When
these are all up and running, the instance is said to be started (see the next section for more
details on starting and stopping a database).
The Oracle database is essentially the collection of database data files, the control file, and
online redo log files. When the instance is running, Oracle will attach to the database and
open it for business. Once the database is open, users can begin to do their work, assuming
there are no problems during the database open process that prevents it from opening.
Sybex's OCA: Oracle Database 12c Administrator Certified Associate Study
Guide provides complete coverage of the Oracle Database memory and
processes. In this text, we assume you have already taken and passed the
OCA exam and that you understand the body of knowledge consanguine-
ous to that exam.
Oracle Database Startup and Shutdown
It is important to understand the startup and shutdown process of an Oracle database.
In this section, we will first discuss the different stages of the Oracle database startup and