Database Credentials screen to configure passwords for the various user accounts that are set up automatically when the database is configured. The password can be either the same or different for all the critical accounts.
Typically, the same critical passwords are set for the preconfigured user accounts and the others are selectively locked.
SYS: The SYS user owns all the internal Oracle tables that constitute the data dictionary. the SYS user and should ensure that this account is locked down. Also, don’t manually modify the underlying objects owned by the SYS user.
SYSTEM: The SYSTEM user account is an additional support user that contains additional administrative tables and views. This account should also be locked down to prevent unauthorized use of it.
DBSNMP: DBSNMP is a login used by the Enterprise Manager facility to monitor and gather performance statistics about the database.
SYSMAN: SYSMAN is the equivalent of the SYS user for the Enterprise Manager facility. This Enterprise Manager administrator can create and modify other Enterprise Manager administrator accounts, as well as administer the database instance itself.
Once the Database Credentials page is completed, click Next. Storage Options screen will be displayed.
The Storage Options screen is used to define how you want to configure the disk storage areas used by the database. There are three options.
File System Storage: File system storage is the most common type of storage configuration for pre–Oracle 10g databases. This type of storage definition relies on the underlying operating system to maintain and manage the actual files that you as the DBA define. When you choose this option, the DBCA suggests a set of datafile names and directory locations for those files. You can modify this information at a later step in the database creation process.
The DBCA uses the Optimal Flexible Architecture (OFA) directory design for laying out the suggested file locations. The OFA is an Oracle-recommended method for designing a flexible directory structure and naming convention for your Oracle database files.
ASM Storage: Automated Storage Management (ASM) is a new type of storage mechanism available in Oracle 10g. ASM is designed to relieve the burden of disk and storage management and relies on Oracle to maintain your database storage. Instead of your managing many individual database files, ASM allows you to define disk groups for file management.
Using disk groups, you can define one or more groups of disks as a logical unit that Oracle views as a single unit of storage. This concept is similar in nature to the way that some operating systems, including various flavors of Unix, define volume groups.
Oracle manages the storage definitions of the database within a second database used exclusively by ASM to keep track of the disk group allocations. When you create a database and select the ASM option in the Storage Options screen, a series of screens guides you through the process of defining the secondary ASM database instance.
For more information on the new ASM feature, see Chapter 12 in the Oracle Database Administrator’s Guide 10g Release 1 (Part Number B10739-01). This book is part of the standard Oracle documentation CD collection that accompanies your Oracle software. You can also find this documentation on the Oracle Technet website at http: //technet.oracle.com. The website is free but you have to create a user ID and password to view the documentation.
Raw Devices: You can also select a raw device as your storage definition. Raw devices are disks that are not managed by the underlying operating system. Instead of the underlying operating system controlling disk reading and writing activities, Oracle performs the actions directly to the underlying hardware without handing the responsibilities off to the operating system.
Typically, the systems administrator predefines the raw disk partitions that will constitute the specific raw devices. Then, you as the DBA map the raw devices to specific datafiles and redo log files.
After the file storage type is defined, it is required to specify location to place these files for the entire database.
If you choose this option, you can specify a new directory for all your database files. Again, even if you choose this option, you can change the filenames and locations later in the database definition process.
Use Oracle-Managed Files: If you chose Automated Storage Management (ASM) on the Storage Options screen, you choose Use Oracle-Managed Files and select the appropriate directory path to the area of the disk that will be used to store the database. This area of disk will be fully managed by a secondary ASM Oracle database. If you choose this option, you will not be able to review or make changes later in the database definition process.