RAC One Node - Expert Oracle RAC 12c - page 420

Instance RONDB_2 is running on node rac2
Instance RONDB_1 is running on node rac1

Scaling Down to RAC One Node
The process to fall back or scale down a RAC database to RAC One Node is pretty simple and straightforward.
However, the following prerequisites must be fulfilled:

• The RAC database must not contain more than one instance. If so, all instances except one

must be stopped and removed from the RAC database to avoid PRCD-1214 : Administrator-
managed RAC database RONDB has more than one instance error. Use the following
commands to stop and remove instance 2:

• Srvctl stop instance -d RONDB -i RONDB_2

• Srvctl remove instance -d RONDB -i RONDB_2

• At the same time, ensure that the instances that are going to be removed are not in the

preferred instances list of any database services. If they are, modify the existing database
services accordingly.

When you've met all the prerequisites, issue the following command to convert a RAC database to a RAC One
Node database:

$ srvctl convert database -d RONDB -c RACONENODE -i RONDB_2 -w 5

When the command completes, your standard RAC database will now be a RAC One Node database. To verify
the database type, use the srvctl config command.

Managing RAC One Node with Cloud Control 12c
As stated earlier, an Oracle RAC One Node database can be thoroughly monitored and managed with Cloud Control
12c. This section is going to demonstrate some of the actions using sequences of screenshots. However, we won't
describe how to install Oracle Enterprise Manager (OEM) agents and discover the targets, as there won't be any
difference with regard to the process as it's usually done.

■ Management with OeM 11gR2 is possible, although making use of Cloud Control 12c is the preferred method.
For this reason, we will limit our discussion to the use of Cloud Control 12c. If you currently have OeM 11gR2, then visit
Oracle Support's website to obtain required patches to make RAC One Node work with OeM 11gR2.

Note

Database Relocation with Cloud Control 12c
To perform relocation, go to the availability pulldown menu. Select Cluster Database Operations ➤ Online Database
Relocation . The screen is shown in Figure 14-8 .