R12 Instance Home Overview

Oracle Applications/E-Business Suite Release 12 introduces a new concept of a top-level directory for an Applications Instance which is known as Instance Home and is denoted the environment variable $INST_TOP
           Instance Home contains all the config files, log files, SSL certificates etc.

Advantages of new INSTANCE HOME

  • The additional Instance Home makes the middle tier more easy to manage and organised since the data is kept separate from the config files. The Instance Home also has the ability to share the Applications and Technology stack code across multiple instances.
  • Another advantage of the Instance Home is that the Autoconfig no longer writes anything to the APPL_TOP and ORACLE_HOME directories, everything is now written in the INST_TOP as a result APPL_TOP and ORACLE_HOME can also be made read only file system if required . Earlier say the adpatch used to write the log file in APPL_TOP/admin directory but with the new model the APPL_CONFIG_HOME/admin is used.
  • To create a new instance that shares an existing middle-tier, just create a new instance_top with proper config files and NFS Mount the middle tier in the server.The basic structure of the Instance Home is:$APPS_BASE/inst/apps/$CONTEXT_NAME  or also defined by environment variable $INST_TOP, where APPS_BASE (which does not have or need a corresponding environment variable) is the top level of the Applications installation and $CONTEXT_NAME  is the highest level at which the Applications context exists (format $SID_$hostname).

    Instance Home Directory Structure

  • $INST_TOP/admin/scripts ($ADMIN_SCRIPTS_HOME): All AD scripts are located here
  • $INST_TOP/appl ($APPL_CONFIG_HOME) : For standalone envs, this is set to $APPL_TOP
    $INST_TOP/appl/fnd/12.0.0/secure FND_SECURE: The dbc file is located here
    $INST_TOP/appl/admin All the env config files are located here
  • $INST_TOP/certs SSL Certificates go here
  • $INST_TOP/logs LOG_HOME: Central log file location. All log files are placed here (except adconfig)
    $INST_TOP/logs/ora ($ORA_CONFIG_HOME)
    $INST_TOP/logs/ora/10.1.2 ‘C’ Oracle home config, Contains tnsnames and forms listener servlet config files
    $INST_TOP/logs/ora/10.1.3 Apache & OC4J config home, Apache, OC4J and opmn. This is the ‘Java’ oracle home configuration for OPMN, Apache and OC4J
  • $INST_TOP/pids  Apache/Forms server PID files are located here
  • $INST_TOP/portal Apache’s DocumentRoot folder
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    9 comments
    rahul says October 19, 2007

    Does it means that we can make the whole appl_top read only and not even a single log file and configuration file is there in the appl_top ?

    Reply
    Atul says October 20, 2007

    Yes if this is single node instalaltion your $APPL_CONFIG_HOME will point to $APPL_TOP (as mentioned by Joyjeet above) but if this is mulinode shared appl_top instance then this will go to $INST_TOP/appl and you can make appl_top read only

    Reply
    Paul says June 9, 2008

    Hi Atul,
    I have a quick question..

    The 8.0.6 ORACLE_HOME in Release 11i is replaced by what in R12?

    Where you configure the APPS_LISTENER in R12?

    Thanks.

    Reply
    Atul says June 9, 2008

    806 is replaced by 10.1.2.X

    Check here http://onlineappsdba.com/index.php/2007/04/08/difference-between-oracle-apps-11i-and-r12-technical/

    Apps listener is under application tier oracle_home i.e. 10.1.2 oracle home for forms (similar to 806 oracle home in 11i)

    Reply
    » Oracle R12/12i log file (Patch, Clone, Startup/Shutdown) Online Apps DBA: One Stop Shop for Apps DBA’s says December 19, 2008

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    » Oracle Apps R12 Interview/Reader’s Question : opmnctl status Online Apps DBA: One Stop Shop for Apps DBA’s says January 4, 2010

    […] is INST_TOP in Oracle Apps ? INST_TOP denotes new TOP in Apps R12 INSTANCE_HOME, more information here . INSTANCE_HOME contains scripts, log and configuration files […]

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    muneer says April 29, 2010

    Hi Joyjeet,

    I could not understand the following.

    “To create a new instance that shares an existing middle-tier, just create a new instance_top with proper config files and NFS Mount the middle tier in the server.”

    I could not understand what is meant by “just creating a new instance_top”. How do I crate a new instance top. Please elaborate.

    Thanks.

    Reply
    » How to configure Load Balancer in Oracle E-Business Suite R12 Online Apps DBA: One Stop Shop for Apps DBA’s says April 21, 2011

    […] is at $INST_TOP/appl/admin) of application tier. To know more about INST_TOP and CONTEXT_FILE click here  and […]

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