ORA-15018, ORA-15072 on 11gR2 grid node 2 when running root.sh

Problem Description
Observation 01:
During installation of Oracle 11gR2 Grid Infrastructure whenever you run root.sh script on second node it fails with error ORA-15018 and ORA-15072 like below.

DiskGroup DATA1 creation failed with the following message:
ORA-15018: diskgroup cannot be created
ORA-15072: command requires at least 1 regular failure groups, discovered only 0

But root.sh ran successfully on node 1.

Observation 02:
On 2nd node after throwing the error crs fails to start and if you look for logfile rootcrs_2ndnodename.log you will see an entry like,

2010-08-09 15:20:12: Configuring ASM via ASMCA
2010-08-09 15:20:12: Executing as oracle: /u01/app/1120/grid/bin/asmca -silent -diskGroupName DATA1 -diskList ORCL:DATA1 -redundancy EXTERNAL -configureLocalASM
2010-08-09 15:20:12: Running as user oracle: /u01/app/1120/grid/bin/asmca -silent -diskGroupName DATA1 -diskList ORCL:DATA1 -redundancy EXTERNAL -configureLocalASM
2010-08-09 15:20:12: Invoking "/u01/app/1120/grid/bin/asmca -silent -diskGroupName DATA1 -diskList ORCL:DATA1 -redundancy EXTERNAL -configureLocalASM" as user "oracle"
2010-08-09 13:20:16: Configuration of ASM failed, see logs for details

Observation 03:
If you look for /etc/oratab file on second node you will see an interesting observation. There is an entry about +ASM1 instead of +ASM2.

Observation 04:
The following commands on the 2nd node show the ASM disk information correctly.
# /etc/init.d/oracleasm listdisks
# /etc/init.d/oracleasm scandisks
# ls -ltr /dev/oracleasm/disks

Observation 05:
While installing Oracle 11gR2 Grid Infrastructure on ASM, it automatically shows all the disks and disk groups without needing to click on "Disk Discovery Path". It showed disk but it added ORCL in the disk name. Suppose, it was shown disk name as ORCL:DATA1, ORCL:DATA2 etc instead of showing as only DATA1, DATA2.

Cause of the Problem
This problem is actually due to oracle bug. All disks were configured properly but due to bug it could not detect the disk rightly and an ORCL is appended which later caused the problem. There is also possible problem if within /etc/sysconfig/oracleasm file, ORACLEASM_SCANORDER and ORACLEASM_SCANEXCLUDE attribute is configured improperly.

Solution of the Problem
Step 01: Deinstall the oracle clusterware installation.
To know how to deinstall oracle clusterware have a look at http://arjudba.blogspot.com/2010/03/what-to-do-after-failure-of-oracle.html

Step 02: While installation whenever it shows the ASM disk automatically, just click on "Disk discovery path" and type the path manually and let the installer to search path there.

However, if there were improper parameters set within /etc/sysconfig/oracleasm file then do the following:

1. In all RAC nodes modify the /etc/sysconfig/oracleasm with:

ORACLEASM_SCANORDER="dm"
ORACLEASM_SCANEXCLUDE="sd"

2. In all nodes restart the asmlib by,

# /etc/init.d/oracleasm restart

3. As root, run "$GRID_HOME/crs/install/rootcrs.pl -verbose -deconfig -force" on all nodes, except the last one. If you have two nodes cluster then only run at first node.
# $GRID_HOME/crs/install/rootcrs.pl -verbose -deconfig -force

$su
# $GRID_HOME/crs/install/rootcrs.pl -verbose -deconfig -force

4. As root, run "$GRID_HOME/crs/install/rootcrs.pl -verbose -deconfig -force -lastnode" on last node. This command will zero out OCR and VD disk also. If you have two nodes cluster then run on second node.

# $GRID_HOME/crs/install/rootcrs.pl -verbose -deconfig -force -lastnode

5. As root, run $GRID_HOME/root.sh on all nodes.
# $GRID_HOME/root.sh
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