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The Database Configuration
Assistant (DBCA) can now be used to fully configure Real Application
Clusters (RAC) environment. In order to use this new feature there
are various prerequisites that must be met:
* Shared disk subsystem must in
place. The details of which were covered extensively in the previous
chapter. RAW partitions or Oracle Cluster File System or a certified
CFS provided by the system vendor must be installed and configured.
If planning to use the ASM, ASM resources (disk devices) should be
* Oracle Cluster Ready Services
must be installed and configured. This encompasses what were
formally Oracle Cluster Manager (oracm) and the global services
daemon (GSD). In addition to GSD, the CRS starts the EVMD, CSSD, and
* The Oracle Database 10g
software must be installed, as described in the previous section.
Once the above prerequisites are
met, the DBCA program will recognize that the system is running in a
clustered environment and will provide the options of configuring
the RAC environment. If the proper services are running, the DBCA
will automatically provide the required configuration screens.
The DBCA processing steps are:
1. Depending on the type of
storage that has been chosen, the DBCA will:
* If using Automatic Storage
Management (ASM), then the DBCA will initialize the ASM subsystem
and then start the ASM instance(s).
* If using CFS (Cluster File
System), then the DBCA will validate the data file destination to be
validly shared across all the nodes that are going to be part of the
* If using raw devices, then the
DBCA will validate the raw device tablespaces sizes and then
validate their access permissions.
2. It obtains a variety of
inputs from the DBA and then it creates the database.
3. It configures the Oracle
4. Then, it creates and starts
the high availability services.
5. Finally, it starts the
listeners and database instances and then starts the high
Creating RAC Database with
Once the DBCA is invoked, the
first page that the DBCA displays is the Welcome page for RAC as
shown in Figure 6.27. However, the DBCA only displays this RAC
specific Welcome page if it detects that the DBCA is running on a
cluster node and the DBCA can communicate with Oracle Cluster Ready
Services (CRS) previously installed by the OUI.
If the DBCA does not display the
Welcome Page for RAC, then the DBCA was unable to detect that the
clusterware (CRS) is running. If this happens, perform clusterware
diagnostics by executing the olsnodes command. Once the DBCA RAC
Welcome screen appears, create a RAC database:
Figure 6.27: DBCA Welcome Page
Select the Real Application
Clusters database option and click Next, and the DBCA will display
the Operations page. The DBCA only enables Instance Management and
Services Management if there is at least one RAC database configured
on the cluster.
Next, select Create A Database
and then click Next, and the DBCA will display the Node Selection
Figure 6.28: DBCA Node Selection
The DBCA will highlight the
local node by default. The DBA must select the other nodes to
configure as members of the cluster database, and then click Next.
The DBCA will then display the Database Templates page. If nodes
that are part of the cluster installation do not appear on the Node
Selection page, perform clusterware diagnostics by executing the
The templates on the Database
Templates page are the Data Warehouse, General Purpose, and
Transaction Processing preconfigured templates. These templates
include data files and specially configured options for each
environment. However, the New Database template does not include
data files or the specially configured options. Use a template with
data files to create a preconfigured database. Select a template
from which to create the cluster database.
Figure 6.29: DBCA Database
Template Selection Page
Then click Next, and the DBCA
will display the Database Identification page.
Figure 6.30: DBCA Database
Then, enter the global database
name and the Oracle system identifier (SID) prefix, as well as the
SYS and SYSTEM user passwords, for the cluster database.
Figure 6.31: DBCA Database
Note: The global database name
is limited to eight characters in length and must begin with an
alphabetical character. The SID prefix must be between one and five
characters in length and also begin with an alphabetical character.
Allow space for as many characters as are required for the numeric
designations of the instances, for example, 1-9 is one character;
10-99 would be two characters. The DBCA uses the SID prefix to
generate a unique value for the oracle_sid for each instance.
Click Next, and the DBCA will
display the Storage Options page. Use the Storage Options page to
select a storage type for database creation. The Cluster File System
option is the default. Select a storage option, click Next, and the
DBCA displays the Database Components page.
Figure 6.32: DBCA Database
At this point a prompt will
appear requesting the Disk Discovery String and ASM parameter file
name and other ASM credentials as shown in Figure 6.33.
Figure 6.33: DBCA ASM Instance
From this page, select the
database components that are required for the database and their
respective default tablespaces, then click Next, and the DBCA will
display the Connection Options page.
On this page, enter the database
connection choices, then click Next, and the DBCA will display the
DBCA Database Services page. In this example, a service called SALES
has been created, which uses two instances with equal preference for
load balancing and follows the basic TAF policy.
Figure 6.34: DBCA Database