ORA-15063: ASM discovered an insufficient number of disks for diskgroup "DATA"

Hello All,

I have normal redundancy diskgroup with the following failure groups:

FAILGROUP:       DISK:

RAC2_HQ           /dev/flashgrid/rac2-hq.lun2     <<< normal disk
RACQ_HQ          /dev/flashgrid/racq-hq.lun3    <<< quorum disk
RAC1_HQ        /dev/flashgrid/rac1-hq.lun2  <<<< normal disk

I have dismounted disgroup  - > I changed permissions for one of the normal disk /dev/flashgrid/rac2-hq.lun2 and tried to mount , getting error:

SQL> alter diskgroup data mount force;

alter diskgroup data mount force

*

ERROR at line 1:

ORA-15032: not all alterations performed

ORA-15017: diskgroup "DATA" cannot be mounted

ORA-15063: ASM discovered an insufficient number of disks for diskgroup "DATA"