What is the OMS(Oracle Management Server) ?

Question

Hi All,
Anyone can explain me what is the OMS (Oracle Management Server)
in Oracle Enterprise Manager(OEM),may be it is the server where OEM resided on when install program I'm not sure?
Thank you,
Mcka

Answer 1

Enterprise manager has two ways of operating: direct attach and three-tier
In Oracle9i, the direct attach is 'stand alone console'. In 10g it is 'db console'
In Oracle9i, the three tier is using an OMS. In 10g, it is called the grid control.
Basically the OMS or Grid Control has the following configuration:
- On each database server, there is an Enterprise Manager Agent. It 'manages' all database instances on that server;
- there is a central application server (Oracle Management Server/OMS) that communicates with all agents. It tells the agent to performan actions (such as collecting operating stats) and it gets the results from those actions;
- there is a central OMS repository (schema in a database) used the the OMS, that is used to store configuration and information retrieved by the agents;
- the OMS responds to user (administrator) requests from the [9i] java console or the [10g] browser. The requested information may be retrieved from the repository or retrieved in real time directly from the instance via the agent.
The OMS can be installed on any machine. The OMS repository can be installed on any machine with a database instance.
Often the database, the OMS and the OMS repository are both installed on a single 'DBA-only machine'. (This makes sense as the information collected could have a SarbOx impact.)