21 Enterprise Manager Configuration Assistant (EMCA)

Configuring Database Control with EMCA

When you use the Database Configuration Assistant (DBCA) to configure Oracle Database 11g, DBCA provides a graphical user interface to help you select Database Control options and to configure other aspects of your database.

However, if you want to use the operating system command line to configure Database Control, you can use the Enterprise Manager Configuration Assistant (EMCA).

To configure Database Control with EMCA:

1. Set the following environment variables to identify the Oracle home and the system identifier (SID) for the database you want to manage:

   • ORACLE_HOME

   • ORACLE_SID

2. Change directory to the ORACLE_HOME/bin directory.

3. Start EMCA by entering the following command with any of the optional command-line arguments shown in Table 21-1:

   $PROMPT> ./emca 
   

   Depending upon the arguments you include on the EMCA command line, EMCA prompts you for the information required to configure Database Control.

   For example, enter the following command to configure Database Control so it will perform automatic daily backups of your database:

   $PROMPT> ./emca -config dbcontrol db -backup
   

EMCA commands are of the form:

emca [operation] [mode] [flags] [parameters]

emca -config dbcontrol db -repos create

Table 21-1 describes the valid execution operations and modes, and lists the optional parameters in brackets. Table 21-2 discusses the flags and their behavior, while Table 21-3 defines the optional parameters in detail. EMCA parameters are of the form [ -parameterName parameterValue ]. Multiple parameters can be used in combination at the command line.

Configuring Software Library With EMCA

As part of Database Control configuration, the software library will be configured and provisioning archives will be deployed. By default, the software library will be configured at the following location:

ORACLE_HOME/EMStagePatches_<db_unique_name>

You can also use the EMCA EM_SWLIB_STAGE_LOC command-line parameter to configure the software library after you have installed and configured Oracle Database 11g.

For Oracle Real Application Clusters (RAC), the software library will be configured and provisioning archives will be deployed only if ORACLE_HOME or the software library location passed to the EM_SWLIB_STAGE_LOC parameter is in shared storage.

Using an Input File for EMCA Parameters

Instead of answering a series of prompts when you run EMCA, you can use the -respFile argument to specify an input file. The input file you create must be in a format similar to the following example:

PORT=1521
SID=DB
DBSNMP_PWD=xpE234D
SYSMAN_PWD=KDOdk432

After you create an EMCA input file, you can use it on the command line as follows:

$PROMPT> ./emca -config dbcontrol db -respFile input_file_path

For example, to configure the Database Control to perform daily backups and create the Database Control Management Repository, create an input file similar to the one shown in Example 21-1 and enter the following command at the operating system prompt:

$PROMPT> ./emca -config dbcontrol db -repos create -backup -respFile input_file_path

PORT=1521
SID=DB
DBSNMP_PWD=dow3l224
SYSMAN_PWD=squN3243
HOST_USER=johnson
HOST_USER_PWD=diTf32of
SYS_PWD=qlKj4352
BACKUP_SCHEDULE=06:30

Using EMCA With Oracle Real Application Clusters

Oracle Real Application Clusters (RAC) provides a high availability database environment spanning multiple hosts. Each cluster may be made up of multiple cluster databases, each of which consists of multiple cluster database instances. A cluster database is available as long as one of its instances is available.

All EMCA commands can be used in Oracle RAC environments; certain commands are only applicable in cluster setups. To indicate that you have a cluster database, use the –cluster flag which is available in almost every EMCA operational mode.

When you use EMCA to configure Database Control for Oracle RAC, you configure the Database Control for each instance in the cluster. However, by default, the Database Control Console will only start on the local node. On every other node of the cluster, only the Enterprise Manager agent will start. This is because the Database Control Console opens a number of connections to the database. If an instance of the console is running on every host in the cluster, then you may easily exceed the maximum number of permitted open connections on a 32-node or 64-node environment.

To remedy this, the Database Control Console is only started on the local node. On every other node, the commands emctl start dbconsole and emctl stop dbconsole only start and stop the agent. Each of the remote agents will upload their respective data to the console running on the local node, from where you can monitor and manage all the targets in the cluster. On each instance of the RAC database, the following subdirectories will be created:

$ORACLE_HOME/hostname1.domainname_SID1
$ORACLE_HOME/hostname2.domainname_SID2
.
.
$ORACLE_HOME/hostnamen.domainname_SIDn

where <SID1>...<SIDn> are database system identifiers.

However, note that if you upgrade an Oracle 10g Release 2 Oracle RAC database configured with Database Control to Oracle 11g Release 1, the 10g Release 2 Database Control configuration will be retained. Database Control for Oracle10g Release 2 has a Database Console running on each Oracle RAC node. The console is still started on each individual node. If you want to modify this configuration, then use the following command:

emca -reconfig dbcontrol –cluster –EM_NODE <nodename> -EM_SID_LIST <SID list>

where <nodename> is the public name of the node and <SID list> is a comma-separated list of database system identifiers. This command reconfigures the current Database Control setup and:

1. Starts a Database Control Console on <nodename>, if one has not been started yet.

2. Redirects the agents monitoring the database instances in <SID list> so that they upload their data to the console running on <nodename>. Also, agents monitoring database instances on <nodename> will also upload their data to the local console. Note that if you do not pass -EM_NODE or -EM_SID_LIST at the command line, you will be prompted for them.

-EM_NODE defaults to the local node if not specified when prompted. -EM_SID_LIST defaults to all database instances if not specified.

You may use this command to start the console on more than one node. For instance, on an 8-node cluster with <node1, node2, node3, node4, node5, node6, node7, node8> and database instances <oradb1, oradb2, oradb3, oradb4, oradb5, oradb6, oradb7, oradb8>, you can run the following commands in succession:

$PROMPT> emca -reconfig dbcontrol –cluster –EM_NODE node1 -EM_SID_LIST oradb2,oradb3,oradb4
$PROMPT> emca -reconfig dbcontrol –cluster –EM_NODE node5 -EM_SID_LIST oradb6,oradb7,oradb8

In this scenario, there will be two Database Control consoles running, one on node1 and the other on node5. From either of these consoles, you can manage and monitor all targets in the cluster.

For information on the current cluster configuration, you can run:

emca -displayConfig dbcontrol –cluster

The above command prompts for the database unique name for the cluster database. This will print the current configuration onto the screen, indicating the nodes that have consoles running on them and the consoles where each agent is uploading.

For configuring Enterprise Manager for a new cluster instance of a database or ASM storage, use the following command:

emca -addInst db

On cluster databases, another common operation is the creation and deletion of database instances. After you create a new instance, you can run EMCA to configure Database Control or central agent management for that instance using the command emca -addInst db. Running EMCA does not create the actual database instance; it only configures Enterprise Manager so that you can manage the instance in a way consistent with the rest of the cluster database instances. When configuring Enterprise Manager for a new instance, run the EMCA command only after you have created the instance. Also, run the command from a node in the cluster that already has Enterprise Manager configured for its associated database instance, as these configuration settings will be propagated to the new instance. Do not run this command from the node on which the new instance was created. Note that this option can be used only in an Oracle RAC environment, so you do not need to use the -cluster option on the command line. After running the command emca -addInst db, enter the following information for the node and database:

Node name: node2
Database Unique Name: EM102
Database SID: EM1022

To deconfigure Enterprise Manager for a specific database instance (typically before the database instance is deleted), use the inverse command, emca -deleteInst db. Running EMCA does not delete the database instance; it only removes the Enterprise Manager configuration so that you will no longer be able to manage the instance with Enterprise Manager. Ensure that you run the EMCA command before you delete the actual cluster database instance. Also, ensure that you run the command from a different node and not from the node on which the database instance will be deleted. Note that this option can be used only in an Oracle RAC environment, so you do not need to use the -cluster option on the command line.

For more information, see Table 21-1 which describes EMCA command-line operations.

Specifying the Ports Used by EMCA

When you initially install Oracle Databse 11g or configure the Database Control with EMCA, the Database Control uses a set of default system ports. For example, by default, you access Database Control using port 1158 in 11g Release 1, as in:

http://host.domain:1158/em

This is the default port assigned to Database Control by the Internet Assigned Numbers Authority (IANA). Likewise, the default Database Control Agent port, as assigned by the IANA, is 3938.

To use ports other than the default ports, use the following EMCA command-line arguments when you initially configure the Database Control with EMCA. Alternatively, you can explicitly assign ports after configuring Database Control using the following command:

emca -reconfig ports [-cluster]

The following list summarizes the EMCA command-line arguments that control the standard Database Control port assignments:

• -DBCONTROL_HTTP_PORT <port_number>

  This port number is used in the Database Control Console URL. For example, if you set this port to 5570, you can then display the Database Control Console using the following URL:

  http://host.domain:5570/em
  

• -RMI_PORT <port_number>

  This port number is used by the Remote Method Invocation (RMI) system, which is part of the J2EE software required by Database Control. The default port can be changed if the user wants to configure a specific port for Database Console. When a port other than the default port (1521) is used, use the -RMI_PORT or -JMS_PORT options along with the emca reconfig command.

• -JMS_PORT <port_number>

  This port is used by the OC4J Java Message Service (JMS), which is part of the J2EE software required by Database Control. The default port can be changed if the user wants to configure a specific port for Database Console. When a port other than the default port (1521) is used, use the -RMI_PORT or -JMS_PORT options along with the emca reconfig command.

• -AGENT_PORT <port_number>

  This port is used by the Database Control Management Agent, which is monitoring and administering the database for the Database Control.

EMCA Troubleshooting Tips

The following section describes some troubleshooting tips to consider when using EMCA to configure the Database Control:

• Using EMCA After Changing the Database Listener Port

• Upgrading Database or ASM Instances With 11g Release 1 Grid Control Agents

• Using EMCA When Database Host Name or IP Address Changes

• Using EMCA When the TNS Configuration Is Changed

emca -deconfig dbcontrol db -repos drop
emca -config dbcontrol db -repos create

emca -deconfig dbcontrol db
emca -config dbcontrol db -repos recreate

emca -config dbcontrol db