Create ASM disk group

1) on ASM instance configure disk group


alter system set asm_diskstring ='ORCL:DGRAID','ORCL:DGFAIL1','ORCL:DGFAIL2' scope=both;
alter system set asm_diskgroup='DGRAID','DGFAIL' scope=both;
** asm_diskstring specifies where the asm instance should look to find drives 
it can use.
for example: '\\.\*:' means all local drives.
'\\.\D:' means D: drive.

2) on ASM instance create disk group

create diskgroup dgfail normal reducdancy
failgroup ctl1 disk '/dev/raw/raw5'
failgroup ctl2 disk '/dev/raw/raw6';

create diskgroup dgraid external redundancy
disk '/dev/raw/raw3';

3) on oracle db instance create tablespace on ASM disk group.


create tablespace iotest datafile
'+DGRAID/iotest.dbf' size 500m reuse
extent management local uniform size 256k
segment space management auto