Shulou(Shulou.com)06/01 Report--

1. OEM knowledge points

1. Introduction to OEM

OEM is a tool set that uses intuitive and convenient graphical interface to control and manage ORACLE database. It contains a large number of useful tools for DBA. In oracle, database management and operations can be done using OEM, such as creating users and roles, permission assignment, creating scheme objects, storage management, and so on.

2. OEM architecture

OEM can manage not only local database instances, but also database instances in network and RAC environments. OEM accesses the database through HTTP/HTTPS, whether it is managing the database locally or on the network. Its architecture is shown below:

1) Management repository: stores the management data and status information of the database to be monitored.

2) OMS management service: monitor and manage the database with management agent installed, and store the management information in management repository.

3) Oracle HTTP Server: built-in apache server.

4) OC4J/J2EE: an application server that conforms to J2EE standards.

5) Oracle web cache: used to quickly access web.

6) Management agent: installed on the managed data server to monitor the running status of the database, resource usage, information changes, etc., transfer the information to OMS,OMS and store the information in repository.

3. Two versions of OEM

There are two different versions of OEM: database control and grid control. Database control is typically used to monitor and manage a local single database or RAC database. Grid control is used to manage large-scale and complex system environment, it can manage the entire infrastructure, including hosts, databases, web servers, listeners, services and so on.

With database control, you usually don't have to configure anything, and when you've created the database using DBCA or oracle universal installer, database control is ready to use. Of course, if you manually created the database through the create database statement, you need to configure database control through EMCA (enterprise manager configuration assistant). Grid control needs to be installed separately from the database, and the installation process and configuration are more complicated.

II. The use of OEM

1. Installation and configuration of OEM

When installing an oracle database through oracle universal install, if you choose to create the database (or create the database directly through DBCA), OEM database control is installed by default. After the database is created, the relevant information of OEM will be displayed, and database control URL is the access address of OEM.

1) use DBCA to configure OEM

DBCA provides a way to create an OEM graphically, starting DBCA first.

In this way, using OEM database control to manage the database is configured, this way is very simple, all through DBCA visualization.

2) manually configure using EMCA

If you create the database manually through the create database statement, you need to configure OEM through EMCA. EMCA can set all aspects related to OEM, such as the reconstruction and deletion of repository storage, the creation and deletion of configuration files, and so on. The following are common EMCA commands.

Emca-config dbcontrol db: configure OEM database control.

Emca-deconfig dbcontrol db: delete the OEM database control configuration file.

Emca-repos drop: delete the repository store.

Emca-repos create: create a new repository store.

Emca-repos recreate: rebuilds the repository store.

Let's reconfigure OEM using emca. Execute the emca-config dbcontrol db-repos recreate command, which configures OEM database control and rebuilds the repository store.

Note: if OEM has not been configured, use the emca-config dbcontrol db-repos create command to configure it.

2. Use EMCTL to control OEM

You must make sure that the dbconsole process is started before using OEM, and oracle provides EMCTL tools to start and shut down the dbconsole process and view its status.

1) View OEM status

By executing the emctl status dbconsole command, you can get whether the OEM is running, the access address of the OEM, and the location of the log. The implementation results are as follows:

3. Use OEM to monitor and manage databases

OEM provides very powerful monitoring and management capabilities, and here are a few common operations.

1) use OEM to start and shut down the database

First, make sure that the monitor is running.

3) access the URL of OEM, and click the "start" button

4) enter the main interface, click "start", enter the following interface, and click "OK" in the upper right corner after filling in.

7) Home directory

The home directory section presents the overall state of the database instance, which is presented graphically, while more specific metrics and contents can be obtained by clicking the corresponding content. For example, to get the details of CPU, click the underlined data under the CPU diagram. Other situations are similar, as shown in the following figure:

8) performance

The performance part mainly provides host monitoring, user connection monitoring and iCompo performance, as well as other related connection options to assist in judgment.

Host monitoring: monitor whether there is a cpu bottleneck. It shows the curve of cpu utilization and clearly shows the level of cpu utilization in different periods. If you find that cpu usage is extremely high in a certain period of time, and there have been performance problems, such as the end user reporting that the application system is slow, then you need to analyze the user session to see which sql is consuming cpu resources.

Average active session monitoring: this is a key part of analyzing performance issues, showing which events the session is waiting for during a certain period of time in the instance, and which sessions are waiting for those events, which are represented in different colors.

9) availability

The availability section focuses on the setup and management of backup and recovery, which will be backed up using OEM below.

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