POiSON WORLD

Features on this R12 INST_TOP

-All the logs files have been moved from APPL_TOP,ORACLE_HOME to this to top

• All configuration files have been moved to INST_TOP
  like
  DBc file
  All the http related config files
  appsweb.cfg
  All the start or stop scripts
  all the OC4J related config files

-we can now share the Apps and technology stack among multiple nodes and even instances (Dev,Test, Production) as all the log and config are located in this top.We will have INST_TOP for each context.

-Configuration and log files are co-located

-Easier collection of instance state
-Minimize disk usage and maximize performance

Filesystem look

/inst/apps/ ($INST_TOP)
• /admin
• /scripts ($ADMIN_SCRIPTS_HOME) All the start and stop are here
• /appl ($APPL_CONFIG_HOME) All the apps env are here
• /fnd/12.0.0/secure ($FND_SECURE) dbc file lis located here
• /certs
• /logs ($LOG_HOME) all the logs are located
• /ora ($ORA_CONFIG_HOME)
/10.1.2
/10.1.3 ($ORACLE_CONFIG_HOME) all the techstack(oacore,forms) related config files
• /pids
• /portal
• /rgf

Some more changes to variable

OA_HTML =$COMMON_TOP/webapps/oacore/html
JAVA_TOP=$COMMON_TOP/java/classes
AF_JLIB=$COMMON_TOP/java/lib
JAVA_BASE=$COMMON_TOP/java/

Advantage  of INST_TOP

-Clear distinction between the shared file system and the file system unique to an instance
-Ability to share code (Apps, technology stack) among multiple  nodes and even instances (Development ,Test, Production)
-Enables split ownership of applications and technology stack file systems
-Improves code safety by making shared file system read-only while not patching
-Configuration and log files are co-located
-Easier collection of instance state
-Ability to use network or local storage for various file system portions
-Minimize disk usage and maximize performance

R12.2 Changes

-R12.2 contains the Fusion Middleware 11g tech-stack. The logfile and configuration files is located in that Oracle Home

–Concurrent Manager log/out files have been moved in Non editioned File system

Where to Put INST_TOP in shared file system

It is recommended to put INST_TOP on local filesystem  in shared APPL_TOP filesystem  architecture. This is because of the Apache mutex problem.Apache performance is highly sensitive to mutex file access latency, and at higher loads is also sensitive to I/Os per second. In case you have INST_TOP on shared filesystem, it is suggested to point these context variable to local file-system

s_lock_pid_dir
s_pids_dir
s_web_pid_file

Conclusion

Hope you like the post on R12 INST_TOP, all the advantages and R12.2 changes.  Please do provide the feedback.