You have to download the deinstall software from 11gR2 download from OTN. Choose "see all" to get to that software.
Here is the demonstration of the deinstall utility:
[oracle@oradba2 deinstall]$ ./deinstall -home /opt/oracle/product/11.2/grid1
ORACLE_HOME = /opt/oracle/product/11.2/grid1
Location of logs /opt/oracle/oraInventory/logs/
############ ORACLE DEINSTALL & DECONFIG TOOL START ############
######################## CHECK OPERATION START ########################
Install check configuration START
Checking for existence of the Oracle home location /opt/oracle/product/11.2/grid
1
Oracle Home type selected for de-install is: SIHA
Oracle Base selected for de-install is: /opt/oracle
Checking for existence of central inventory location /opt/oracle/oraInventory
Checking for existence of the Oracle Grid Infrastructure home /opt/oracle/produc
t/11.2/grid1
Install check configuration END
Traces log file: /opt/oracle/oraInventory/logs//crsdc.log
Network Configuration check config START
Network de-configuration trace file location: /opt/oracle/oraInventory/logs/netd
c_check22387.log
Specify all Oracle Restart enabled listeners that are to be de-configured [LISTE
NER]:
Network Configuration check config END
Asm Check Configuration START
ASM de-configuration trace file location: /opt/oracle/oraInventory/logs/asmcadc_
check22388.log
Automatic Storage Management (ASM) instance is detected in this Oracle home /opt/oracle/product/
11.2/grid1.
ASM Diagnostic Destination : /opt/oracle
ASM Diskgroups : +DATA1,+FRA1
Diskgroups will be dropped
De-configuring ASM will drop all the diskgroups and it's contents at cleanup time. This will aff
ect all of the databases and ACFS that use this ASM instance(s).
After some initial question and answer it shows a summary of activities and prompts you for a confirmation:
####################### CHECK OPERATION SUMMARY #######################
Oracle Grid Infrastructure Home is: /opt/oracle/product/11.2/grid1
The cluster node(s) on which the Oracle home exists are: (Please input nodes seperated by ",", eg: node1,node2,...)null
Oracle Home selected for de-install is: /opt/oracle/product/11.2/grid1
Inventory Location where the Oracle home registered is: /opt/oracle/oraInventory
Following Oracle Restart enabled listener(s) will be de-configured: LISTENER
ASM instance will be de-configured from this Oracle home
Do you want to continue (y - yes, n - no)? [n]: y
A log of this session will be written to: '/opt/oracle/oraInventory/logs/deinstall_deconfig2009-09-02_02-12-22-PM.out'
Any error messages from this session will be written to: '/opt/oracle/oraInventory/logs/deinstall_deconfig2009-09-02_02-12-22-PM.err'
After you press "y", it starts the operation of a clean deinstallation. The output continues as shown below:
######################## CLEAN OPERATION START ########################
ASM de-configuration trace file location: /opt/oracle/oraInventory/logs/asmcadc_clean22389.log
ASM Clean Configuration START
ASM deletion in progress. This operation may take few minutes.
ASM Clean Configuration END
Network Configuration clean config START
Network de-configuration trace file location: /opt/oracle/oraInventory/logs/netdc_clean22390.log
De-configuring Oracle Restart enabled listener(s): LISTENER
De-configuring listener: LISTENER
Stopping listener: LISTENER
Listener stopped successfully.
Unregistering listener: LISTENER
Listener unregistered successfully.
Deleting listener: LISTENER
Listener deleted successfully.
Listener de-configured successfully.
De-configuring Listener configuration file...
Listener configuration file de-configured successfully.
De-configuring Naming Methods configuration file...
Naming Methods configuration file de-configured successfully.
De-configuring backup files...
Backup files de-configured successfully.
The network configuration has been cleaned up successfully.
Network Configuration clean config END
---------------------------------------->
At some point you will be asked to shutdown cssd, etc. which need root privileges. The deinstall utility shows a comamnd string you can run as root to accomplish this task:
Run the following command as the root user or the administrator on node "oradba2".
/opt/oracle/software/11gR2/deinstall/perl/bin/perl -I/opt/oracle/software/11gR2/deinstall/perl/lib -I/opt/oracle/software/11gR2/deinstall/crs/install /opt/oracle/software/11gR2/deinstall/crs/install/roothas.pl -force -delete -paramfile /opt/oracle/software/11gR2/deinstall/response/deinstall_Ora11g_gridinfrahome1.rsp
Press Enter after you finish running the above commands
Running the command on a different terminal as root:
[root@oradba2 ~]# /opt/oracle/software/11gR2/deinstall/perl/bin/perl -I/opt/oracle/software/11gR2/deinstall/perl/lib -I/opt/oracle/software/11gR2/deinstall/crs/install /opt/oracle/software/11gR2/deinstall/crs/install/roothas.pl -force -delete -paramfile /opt/oracle/software/11gR2/deinstall/response/deinstall_Ora11g_gridinfrahome1.rsp
2009-09-02 14:20:57: Checking for super user privileges
2009-09-02 14:20:57: User has super user privileges
2009-09-02 14:20:57: Parsing the host name
Using configuration parameter file: /opt/oracle/software/11gR2/deinstall/response/deinstall_Ora11g_gridinfrahome1.rsp
CRS-2673: Attempting to stop 'ora.cssd' on 'oradba2'
CRS-2677: Stop of 'ora.cssd' on 'oradba2' succeeded
CRS-4549: Stopping resources.
CRS-2673: Attempting to stop 'ora.diskmon' on 'oradba2'
CRS-2677: Stop of 'ora.diskmon' on 'oradba2' succeeded
CRS-4133: Oracle High Availability Services has been stopped.
ACFS-9200: Supported
Successfully deconfigured Oracle Restart stack
Now going back to the original terminal where deinstall was called from, press Enter. The output continues:
Oracle Universal Installer clean START
Detach Oracle home '/opt/oracle/product/11.2/grid1' from the central inventory on the local node : Done
Delete directory '/opt/oracle/product/11.2/grid1' on the local node : Done
The Oracle Base directory '/opt/oracle' will not be removed on local node. The directory is in use by Oracle Home '/opt/oracle/product/10.2/db1'.
The Oracle Base directory '/opt/oracle' will not be removed on local node. The directory is in use by central inventory.
Oracle Universal Installer cleanup was successful.
Oracle Universal Installer clean END
Oracle install clean START
Clean install operation removing temporary directory '/tmp/install' on node 'oradba2'
Oracle install clean END
Moved default properties file /opt/oracle/software/11gR2/deinstall/response/deinstall_Ora11g_gridinfrahome1.rsp as /opt/oracle/software/11gR2/deinstall/response/deinstall_Ora11g_gridinfrahome1.rsp1
######################### CLEAN OPERATION END #########################
####################### CLEAN OPERATION SUMMARY #######################
ASM instance was de-configured successfully from the Oracle home
Following Oracle Restart enabled listener(s) were de-configured successfully: LISTENER
Oracle Restart was already stopped and de-configured on node "oradba2"
Oracle Restart is stopped and de-configured successfully.
Successfully detached Oracle home '/opt/oracle/product/11.2/grid1' from the central inventory on the local node.
Successfully deleted directory '/opt/oracle/product/11.2/grid1' on the local node.
Oracle Universal Installer cleanup was successful.
Oracle install successfully cleaned up the temporary directories.
#######################################################################
############# ORACLE DEINSTALL & DECONFIG TOOL END #############
The components are cleanly deinstalled now. The directories have been cleaned up by this tool.
This was available in 11gR1 as well; but R2 just makes it very user friendly.