ASM DISKS ARE NOT VISIBLE IN GRID INSTALLATION 12C
Cause:
When i am installing grid software for clusterware, ASM disks are not visible.This looks pretty weird whenever i face this issue.
Workaround:
There are multiple reasons for the ASM disks to be not visible
Permission issue:
Grant the required permissions to the logical disks as per you project security policies
[root@dc01x01 ~]# ls -lHL /dev/oracleasm/
total 0
drwxrwxrwx 1 oracle oinstall 0 Sep 17 17:59 disks
drwxrwxrwx 1 oracle oinstall 0 Sep 17 17:59 iid
[root@dc01x01 ~]# ls -lHL /dev/oracleasm/disks/
total 0
brwxrwxrwx 1 oracle oinstall 8, 1 Sep 17 17:59 DATAC1
brwxrwxrwx 1 oracle oinstall 8, 17 Sep 17 17:59 DATAC2
brwxrwxrwx 1 oracle oinstall 8, 49 Sep 17 17:59 RECOC1
brwxrwxrwx 1 oracle oinstall 8, 33 Sep 17 17:59 RECOC2
brwxrwxrwx 1 oracle oinstall 8, 65 Sep 17 17:59 REDO01
brwxrwxrwx 1 oracle oinstall 8, 81 Sep 17 17:59 REDO02
brwxrwxrwx 1 oracle oinstall 8, 97 Sep 17 17:59 VODOCR
Give rw or rwx permission and proper ownership of the group in the disks
[root@dc01x01 ~]# chmod -R 777 /dev/
[root@dc01x01 ~]# chown -R oracle:oinstall /dev/oracleasm/
Disk path not specified properly:
Specify the right disk path for the oracleasm driver to read the ASM disk header.
Former disks:
If the ASM disk is already a former disk which was used and dropped previously, then wipe out the metadata information of the disk using dd command to reuse the disk for new installation