What is Oracle Applications/Oracle e-Business Suite ??

To facilitate big businesses, Oracle Corporation have created collection of software in the category of ERP (Enterprise Resource Planning) known as modules, that are integrated to talk to each other and known as Oracle Applications or E-Business Suite.

Eg.
 Oracle Inventory deals with the items you maintain in stock, warehouse etc.
 Oracle Receivables and Oracle Order Management are dealing with customers like orders given by Customers and Money collected from customers.
 Oracle General Ledger receives information from all the different transaction modules and summarizes them in order to create profit and loss statements, reports for paying Taxes etc. 
 Oracle Cost Management helps to maintain the costs of items in your inventory and the immediate modules that it interacts with are Oracle Inventory, Oracle Bills of Material, Order Management.

Oracle Applications Previous Releases

10.7 : Oldest Release of Oracle ERP which is character, thin client based. Oracle has stopped support for this release from year 1998.
11 : 
11i : 
R12 : Latest Release by Oracle In the chain of Oracle ERP Releases.

Whats new in Oracle Apps R12

    Oracle Applications Release 12 is the latest release in the chain of E-Business Suite Releases by Oracle. This is a step towards Oracle Fusion as this uses Oracle Fusion Middleware applications in its base e.g. Oracle application Server 10g, Oracle BI Discoverer 10g etc.
    This release came up with the new file system model i.e. segregation of Code, Data and Configurations to have easy maintenance and to avert NFS mount issues on shared Application tier configuration systems. Also

Autoconfig will not write anything in APPL_TOP, COMMON_TOP area in R12. All instance specific configurations, log files are written in INST_TOP area. Instance Home provides the ability to share Applications and technology stack code among multiple instances.

    The major changes in this release are : 
On Middle Tier 

·         Application Server version 1.0.2.2.2 is changed by 10g Application Server i.e. 10.1.3.X

·         mod_jserv is replaced by mod_oc4j

·         Apache which is part of Application Server mentioned above is changed from version 1.3.19 to 1.3.34

·         Long running Forms & Reports Version 6i (8.0.6) are replaced by Forms & Reports Version 10g i.e. 10.1.2.X

·         Java/ JDK version 1.3.X or 1.4.X will be replaced by JDK 1.5.X

On File System 

·         There are three ORACLE_HOME, one for Web Server another for Forms & Reports and third for Database with the upgraded versions i.e.10g AS for Web Server, 10g AS for forms & reports , 10g R2 for database

·         A new top INSTANCE_TOP is introduced in Release 12 for configuration and log files along with the other TOP's in existing in 11i.

    

Oracle Apps R12 Architecture

R12 file system has come up with new model - Code, Data, Configurations are segregated nicely to have easy maintenance, to avert NFS mount issues on shared appl tier configuration systems. Auto-config will not write anything in APPL_TOP, COMMON_TOP area in R12. All instance specific configurations, log files are written in INST_TOP area. Instance Home provides the ability to share Applications and technology stack code among multiple instances

In Release 12, the application tier contains Oracle Application Server 10g (OAS10g). Three servers or service groups comprise the basic application tier for Oracle Applications: 

·         Web services

The Web services component of Oracle Application Server processes requests received over the network from the desktop clients. 

·         Forms services

Forms services in Oracle Applications Release 12 are provided by the Forms listener servlet or Form Socket mode, which facilitates the use of firewalls, load balancing, proxies, and other networking options. 

·         Concurrent Processing server

Processes that run on the Concurrent Processing server are called concurrent requests. When you submit such a request, either through HTML-based or Forms-based Applications, a row is inserted into a database table specifying the program to be run. A concurrent manager then reads the applicable requests in the table, and starts the associated concurrent program. 

Note: There is no concept of an Administration server in Release 12. By default, patching can be undertaken from any application tier node.

Techstack Components:

DB_TIER

·         10.2.0.2 RDBMS ORACLE_HOME

APPL-TIER

·         10.1.2 C ORACLE_HOME / FORMS ORACLE_HOME (8.0.6 ORACLE HOME equivalence)‏

·         10.1.3 Java ORACLE_HOME/OC4J ORACLE_HOME (iAS ORACLE_HOME equivalence)‏

·         INSTANCE_TOP : Each application tier has a unique Instance Home file system associated

R12 E-Biz and Application Server 10g

There are two versions of Oracle Application server 10g (oAS10g) used, 

·         The Oracle Application Server 10.1.2 ORACLE_HOME (sometimes referred to as the Tools, C, or Developer ORACLE_HOME) replaces the 8.0.6 ORACLE_HOME provided by Oracle9i Application Server 1.0.2.2.2 in Release 11i.

·         The Oracle Application Server 10.1.3 ORACLE_HOME (sometimes referred to as the Web or Java ORACLE_HOME) replaces the 8.1.7-based ORACLE_HOME provided by Oracle9i Application Server 1.0.2.2.2 in Release 11i.

Hence to take advantage of latest oc4j code 10.1.3 AS got introduced. But to support ebiz forms applications 10.1.2 AS introduced.

                                                    R12 e-Biz Oracle Homes

R12 E-Biz Directory Structure

    Below Image describes the complete directory structure for complete e-biz installation i.e. DB_TOP, APPL_TOP and new INST_TOP. If you dig into the INST_TOP you will find that it only contains all the configuration files, start-stop scripts, log files, certificate files, pid files etc.., so as to make DB_TOP and APPL_TOP untouched for any instance specific changes. So you can also make DB_TOP and APPL_TOP read only.

INSTANCE TOP 
       Instance home is the top-level directory for an Applications Instance which is known as Instance Home and is denoted the environment variable $INST_TOP. This 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 organized 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 writes only in INST_TOP so APPL_TOP and ORACLE_HOME can also be made read only file system if required.

·          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

INSTANCE TOP - STRUCTURE 
$INST_TOP: $APPS_BASE/inst/apps/$CONTEXT_NAME/
/admin
    /scripts                    :  ADMIN_SCRIPTS_HOME: Find all AD scripts here
/appl                            :  APPL_CONFIG_HOME. For standalone envs, this is set to $APPL_TOP
    /fnd/12.0.0/secure    : FND_SECURE: dbc files here
    /admin                     : All Env Config files here
/certs                          : SSL Certificates go here
/logs                           : LOG_HOME: Central log file location. All log files are placed here (except adconfig)
/ora                            : ORA_CONFIG_HOME
    /10.1.2                    : 'C' Oracle home config, Contains tnsnames and forms listener servlet config files
    /10.1.3                    : Apache & OC4J config home, Apache, OC4J and opmn
                                    This is the 'Java' oracle home configuration for OPMN, Apache and OC4J
/pids                           : Apache/Forms server PID files here
/portal                         : Apache's DocumentRoot folder

Shared Application Tier File System

      We can configure multiple application node machines working with a single E-Business Suite database node. This creation of a "multi-node" E-Business Suite instance is frequently done to lower cost of ownership (many small machines are cheaper than one big one), increase fault tolerance (one machine fails, others do not), or scale the instance (support more users and a greater load).
      When configuring Oracle E-Business Suite to use a shared application tier file system, the application tier node can be configured to perform any of the standard application tier services, such as Forms, Web, and Concurrent Processing (Batch).
Note the following definitions:
Node
    A node/server/instance is a logical set of processes running on one hardware machine. In a single-node installation of Oracle E-Business Suite, all the Applications processes (including the database processes) run on one node, whereas in a multi-node installation, the processes are distributed across multiple nodes. 
    A multi-node installation of Release 12 supports both shared and non-shared application tier file systems. An application tier file system consists of:

·         APPL_TOP file system (APPL_TOP and COMMON_TOP directories).

·         Application tier technology stack file system (OracleAS 10.1.2 and 10.1.3 Oracle Homes).

·         Instance Home (INST_TOP) file system. Each application tier has a unique Instance Home file system associated with it.

Service
    A service is a functional set of Oracle E-Business Suite application processes running on one or more nodes. Where applicable, the term 'service' is replacing the more traditional term of 'server'.
Application Tier Services
The following are the major application tier services:

·         Root services

·         Web Entry Point services

·         Web Application services

·         Batch Processing services

·         Other services

So if you have two nodes,one will serve as Primary Node and other will serve as Secondry Node. You can configure both the Application tier node as follows:
Primary Application Tier Node
     A primary application tier node is the first application tier node where the APPL_TOP, COMMON_TOP, OracleAS 10.1.2 Oracle Home and OracleAS 10.1.3 Oracle Home are installed and configured. 
Secondary Application Tier Node
     A secondary application tier node is an application tier node where APPL_TOP, COMMON_TOP, 10.1.2 Oracle Home and 10.1.3 Oracle Home are visible and configured. The APPL_TOP, COMMON_TOP, OracleAS 10.1.2 Oracle Home and OracleAS 10.1.3 Oracle Home file system is mounted to this node from the primary application tier node, or from an NFS server. 
Instance Home
Note :  In a shared file system, each application tier will have a unique Instance Home, which should be located on the local file system.

Shared Application Tier File System Architecture

In a shared file system, all application tier files (with the specific exception of the Instance Home file system) are installed on a shared disk resource, which is mounted on each application tier node. Any application tier node can be configured to perform any of the standard application tier services, such as Forms, Web and Concurrent Processing (Batch) services. All changes made to the shared file system are immediately accessible to all application tier nodes.

Shared Application Tier File System Layout

     When configuring Oracle E-Business Suite to use a shared application tier file system, an application tier node can be configured to perform any of the standard application tier services, such as Forms, Web, or Concurrent Processing (Batch) services. An application tier will have a unique Instance Home associated with it that cannot be shared with other application tiers. You can configure the services running on an application tier node to match the node's intended role

Example Shared File System
      The following is an example of mount points shared on each application tier node:

·         COMMON_TOP: /ebiz/oracle/VIS/apps/apps_st/comn

·         APPL_TOP: /ebiz/oracle/VIS/apps/apps_st/appl

·         OracleAS 10.1.2 ORACLE_HOME: /ebiz/oracle/VIS/apps/tech_st/10.1.2

·         OracleAS 10.1.3 ORACLE_HOME: /ebiz/oracle/VIS/apps/tech_st/10.1.3

      In the figure shown below, entitled "Shared Application Tier File System", Server-appl_node1 is the primary application tier node, and uses the file systems “/ebiz/oracle/VIS" and “/ebiz/oracle/inst”. The file system “/ebiz/oracle/inst” contains the Instance Home, and "/ ebiz/oracle/VIS " contains the APPL_TOP, COMMON_TOP, OracleAS 10.1.2 and 10.1.3 Oracle Home. 
      Server-appl_node2 is the secondary application tier node, and the shared file system “/ebiz/oracle/VIS" is also mounted on this node. The file systems "/ebiz/oracle/inst/apps/VIS_appl_node1" and "/ebiz/oracle/inst/apps/VIS_appl_node2" are only visible on the respective nodes.