2 Replies Latest reply: Oct 30, 2012 1:32 PM by RCE RSS



      I've been trying to get this straight in my head but I'm still having problems.

      What is Oracle Home? http://docs.oracle.com/cd/E24628_01/install.121/e24089/getstrtd_things_to_know.htm#CEGJBDBJ

      I had been setting AGENT_HOME to what is, in reality, the AGENT_INSTANCE_HOME because it has to be a static directory path (unaffected by upgrades).

      For example, using the document:

      AGENT_BASE=/u01/app/oracle/agent (unlike the document, I did not capitalize the O in Oracle because we've always had lower case paths)



      That established, I was using emctl located at $AGENT_INSTANCE_HOME/bin/emctl to start/stop my Agent. That seems to be correct. So far so good?

      However, since all the configuration files appear to be in the AGENT_INSTANCE_HOME, I had set the AGENT_HOME to $AGENT_BASE/agent_inst (what is really the AGENT_INSTANCE_HOME).

      The primary benefit to using the agent_inst path for AGENT_HOME is we shouldn't have to change directory paths for Agent upgrades. When we went from to then we would have to change the AGENT_HOME environment variable on all of our hosts -- not difficult but seemingly unnecessary if we can use AGENT_HOME=$AGENT_BASE/agent_inst instead.

      A few questions include:

      1. Is it wrong to use the agent_inst directory for AGENT_HOME and if so, what is the risk?
      2. What is the AGENT_INSTANCE_HOME for and why are those outside of the AGENT_HOME directory?
      3. Would I ever have multiple AGENT_INSTANCE_HOMEs on a single system?
      4...... did I miss anything ?

      Thanks all,

        • 1. Re: AGENT_HOME versus AGENT_INSTANCE_HOME in 12c
          Venkata Thiruveedhi-Oracle
          Hi Rich,

          We should not use the <AGENT_INSTANCE_HOME> location as <AGENT_HOME>.

          Here i am providing the explanation of each location and what is the difference b/w the directories.

          Oracle Management Agent Base directory:
          Also referred to as <AGENT_BASE> or <AGENT_BASE_DIR>, this is the root of the 12c Agent installation.

          * This contains multiple Homes for the Agent software bits, plugins, setuid binaries and the Agent State Home.
          * The agentimage.properties file located in this directory contains the OS details and version of the Agent installation.

          Management Agent Home:
          Also referred to as <AGENT_HOME> or Core Home, this contains all the binaries required to configure and run the Oracle Management Agent on this host. The default location is <AGENT_BASE>/core/

          * The bin directory contains binaries for the Agent.
          * The cfgtoollogs directory contains the Agent installation and configuration logs.
          * The jdk directory contains the Java used by the Agent.
          * The sysman/admin directory contains the files used by the Oracle Management Agent for administrative tasks:
          o metadata: contains the metric metadata for Agent core target types (such as hosts, agent etc).
          o default_collection: contains the default metric collection frequencies for the Agent core target types (host, agent, etc).
          o scripts: contains the scripts used for the metric collection for the agent core target types.
          o nsupportedtzs.lst, supportedtzs.lst: List of timezones supported by the Agent.
          Oracle Management Agent Instance Home:
          Also referred to as the Agent State home or <AGENT_INSTANCE_HOME> or <EMSTATE>, this is the location where the 12c Agent instance files are created.

          * The bin directory in this home contains wrapper scripts that set the appropriate environment variables and redirect to the executables/perl scripts in the <AGENT_HOME>/bin directory.
          So, ideally you could start the 12c Agent using the emctl from <AGENT_HOME>/bin or the <AGENT_INSTANCE_HOME>/bin.
          * The diag directory contains incidents and diagnostic dumps for the Agent.
          * The sysman directory is accessible only to the OS user who has installed the Agent and in turn consists of the following important directories:
          o config: Contains the configuration files for the Agent, including the main configuration file named emd.properties
          o emd: Contains files with Target details such as targets.xml, blackouts.xml etc and also the information that the Agent has collected for the targets.
          o log: Contains the log files for the Agent.
          * This need not always be present under <AGENT_BASE>. In the case of NFS installations, the Agent State Directory is deployed on the remote hosts and not placed under <AGENT_BASE>.

          Oracle Management Agent plugins directory:
          This is the location containing the plugins installed at the Agent side. Default location is <AGENT_BASE>/plugins.

          * All the Agent-side Plugins get deployed in this location.
          * Each plugin directory has its own metric metadata, default_collections and scripts directories specific to the target types supported by that plugin.
          * The list of plugins installed can be obtained from <AGENT_HOME>/sysman/install/plugins.txt.
          * The status of the all the plugin installations can be viewed from <AGENT_HOME>/sysman/install/plugins.txt.status.

          • 2. Re: AGENT_HOME versus AGENT_INSTANCE_HOME in 12c
            Hi Venkat,

            Thank you for the prompt response!

            Please correct me if I'm wrong, but it sounds like the AGENT_INSTANCE_HOME is more for NFS (Shared) Agents than the typical/standard agent deployment. Would this be a fair statement? This would be the only time I might have more than one AGENT_INSTANCE_HOME for an AGENT_HOME? But they would not be on the same system, is my understanding.


            Do you see the problem I have with using the suggested AGENT_HOME that changes based on the version of the Agent installed? I will use the correct AGENT_HOME but when the version changes it will require changes to environment variables that could/should be static.

            With the Oracle DB, for example, the only time we change ORACLE_HOME is with a major version upgrade (migrating from 10.2 -> 11.2 or 11.1 -> 11.2) not with minor releases (PS ->

            Although it seems is considered 12cR1 and is considered 12cR2. Is this correct? This is a deviation from the standard numbering, will this be the new standard for all of Oracle? For just EM or is this a special case?