The inventory is a very important part of the Oracle Universal Installer. oraInventory is repository (directory) which store/records oracle software products & their oracle_homes location on a machine.
Before OUI 2.X the inventory was binary, the binary orainvenory maintains in inventory in binary format
Starting from OUI 2.X and higher information in the inventory is stored in the Extensible Markup Language (XML) format
The XML format allows easier diagnostic of the problem and faster loading of data.
There are two inventories with the newer releases of OUI (2.x and higher):
There is one Local inventory per ORACLE_HOME.
Inventory inside each Oracle Home is called as local Inventory or oracle_home Inventory. This Inventory holds information to that oracle_home only.
The central inventory directory outside the ORACLE_HOME (Global Inventory)
This inventory stores information about.
All the Oracle software products installed on all ORACLE_HOMES on a machine,These products can be various oracle components like database, oracle application server, collaboration suite, soa suite, forms & reports or discoverer server.
Other non-oracle products such as Java Runtime env’s (JRE)
At startup, the Oracle Universal Installer first looks for the key that specifies where the global inventory is located at (this key varies by platform).
/etc/oraInst.loc (AIX and Linux)
HKEY_LOCAL_MACHINE -> Software -> Oracle -> INST_LOC (Windows platforms)
If this key is found, the directory within it will be used as the global inventory location.
If the key is not found, the inventory path will default created as follows:
UNIX : ORACLE_BASE\oraInventory
WINDOWS : c:\program files\oracle\Inventory
If the ORACLE_BASE environment variable is not defined, the inventory is created at the same level as the first Oracle home. For
example, if your first Oracle home is at /private/ORACLEHome1, then, the inventory is at /private/oraInventory.
If you want to see list of oracle products on machine check for file inventory.xml under ContentsXML in oraInventory
multiple Global Inventory on a machine
YES you can have multiple global Inventory
Global Inventory is corrupted ?
No need to worry if your global Inventory is corrupted, you can recreate global Inventory on machine using Universal Installer and attach already Installed oracle home by option
./runInstaller -silent -attachHome -invPtrLoc $location_to_oraInst.loc