Creation of oracleasm disks failed on OEL 5.7 64-Bit. It failed with the following error message:

[root@ebsnode1 ~]# oracleasm createdisk /dev/sdb1 GIDISK1
Disk label "/dev/sdb1" contains an invalid character
[root@ebsnode1 ~]# oracleasm createdisk GIDISK1 /dev/sdb1
Writing disk header: done
Instantiating disk: failed
Clearing disk header: done
[root@ebsnode1 ~]#

Usually we will face such Issues if there is a Firewall/SELINUX option is enabled on the server operating system. We need to make sure that these 2 options are disabled before configuring the oracleasm drivers.

In my configuration I disabled these two options before configuring the oracleasm drivers.

>> Verify SELINUX is disabled on both the nodes:

[root@ebsnode1 ~]# getenforce
Disabled
[root@ebsnode1 ~]#

Cause:

oracleasm drivers was not started and loaded after configuration.

[root@ebsnode1 ~]# oracleasm status
Checking if ASM is loaded: no
Checking if /dev/oracleasm is mounted: no

Solution:

Start the oracleasm drivers on both the nodes after manually after configuring the oracleasm drivers.

[root@ebsnode1 ~]# /etc/init.d/oracleasm start
Initializing the Oracle ASMLib driver: [ OK ]
Scanning the system for Oracle ASMLib disks: [ OK ]
[root@ebsnode1 ~]# oracleasm status
Checking if ASM is loaded: yes
Checking if /dev/oracleasm is mounted: yes

Now try to create the disk, it should be created without any Issues.

>> On node 2 also after configuration oracleasm drivers was not started:

[root@ebsnode2 Server]# oracleasm configure -i
Configuring the Oracle ASM library driver.

This will configure the on-boot properties of the Oracle ASM library
driver. The following questions will determine whether the driver is
loaded on boot and what permissions it will have. The current values
will be shown in brackets ('[]'). Hitting without typing an
answer will keep that current value. Ctrl-C will abort.

Default user to own the driver interface []: oraprod
Default group to own the driver interface []: dbaerp
Start Oracle ASM library driver on boot (y/n) No: y
Scan for Oracle ASM disks on boot (y/n) Yes: y
Writing Oracle ASM library driver configuration: done
[root@ebsnode2 Server]#

>> oracleasm scandisks was not able to scan the configured disks on node1

[root@ebsnode2 Server]# oracleasm scandisks
Reloading disk partitions: done
Cleaning any stale ASM disks...
Scanning system for ASM disks...
Instantiating disk "GIDISK1"
Unable to instantiate disk "GIDISK1"
Instantiating disk "DBDISK1"
Unable to instantiate disk "DBDISK1"
Instantiating disk "VOLDISK1"
Unable to instantiate disk "VOLDISK1"
[root@ebsnode2 Server]#

>> Now after starting and loading the drivers it scanned all configured oracleasm disks.

root@ebsnode2 Server]# cat /etc/redhat-release
Red Hat Enterprise Linux Server release 5.7 (Tikanga)
[root@ebsnode2 Server]# /etc/init.d/oracleasm status
Checking if ASM is loaded: no
Checking if /dev/oracleasm is mounted: no
[root@ebsnode2 Server]# /etc/init.d/oracleasm start
Initializing the Oracle ASMLib driver: [ OK ]
Scanning the system for Oracle ASMLib disks: [ OK ]
[root@ebsnode2 Server]# /etc/init.d/oracleasm status
Checking if ASM is loaded: yes
Checking if /dev/oracleasm is mounted: yes
[root@ebsnode2 Server]# oracleasm scandisks
Reloading disk partitions: done
Cleaning any stale ASM disks...
Scanning system for ASM disks...
[root@ebsnode2 Server]# oracleasm listdisks
DBDISK1
GIDISK1
VOLDISK1
[root@ebsnode2 Server]#

It is always recommenced to reboot the system before actually you start the Installation of Grid Infrastructure Software.

If there are multiple nodes in a cluster and rebooting of nodes is may take long time, In such situations I believe restart if oracleasm drivers should be sufficient.

Thanks for reading.

regards,
X A H E E R