Adding New ASM Disk into Existing Diskgroup.

STEP 1: RUN BELOW QUERY TO CHECK FOR AVAILABLE DISKS FOR ADDING TO THE DISKGROUP
select path,os_mb/1024,header_Status from v$asm_Disk where header_Status!='MEMBER';
select name,total_mb/1024,free_mb/1024 from v$asm_diskgroup;
select path,os_mb/1024,header_Status from v$asm_Disk where header_Status!='MEMBER';
select name,state from v$asm_diskgroup;
OPTIONAL:
create diskgroup TEST01 external redundancy disk '/dev/testdb_32_disk';
select name,state from v$asm_diskgroup;
drop diskgroup TEST01;  
select path,os_mb/1024,header_Status from v$asm_Disk where header_Status!='MEMBER';
If we drop the diskgroup the disk's header status canged to FORMER.
STEP 2: RUN THE BELOW COMMAND TO ADD THE DISK TO THE DISKGROUP
alter diskgroup DATA01 add disk '/dev/testdb_32_disk'rebalance power 5; 
STEP 3: RUN THE BELOW QUERY TO CHECK THE REBALANCE STATUS:
select * from v$asm_operation;
select path,os_mb/1024,header_Status from v$asm_disk where group_number=3;
header status should so MEMBER now.

NOTES:

H E A D E R S T A T U S

§  UNKNOWN - Automatic Storage Management disk header has not been read

§  CANDIDATE - Disk is not part of a disk group and may be added to a disk group with the ALTER DISKGROUP statement

§  INCOMPATIBLE - Version number in the disk header is not compatible with the Automatic Storage Management software version.

§  PROVISIONED - Disk is not part of a disk group and may be added to a disk group with the ALTER DISKGROUP statement. The PROVISIONED header status is different from the CANDIDATE header status in that PROVISIONED implies that an additional platform-specific action has been taken by an administrator to make the disk available for Automatic Storage Management.

§  MEMBER - Disk is a member of an existing disk group. No attempt should be made to add the disk to a different disk group. The ALTER DISKGROUP statement will reject such an addition unless overridden with the FORCE option

§  FORMER - Disk was once part of a disk group but has been dropped cleanly from the group. It may be added to a new disk group with the ALTER DISKGROUP statement.

§  CONFLICT - Automatic Storage Management disk was not mounted due to a conflict
§  FOREIGN - Disk contains data created by an Oracle product other than ASM. This includes datafiles, logfiles, and OCR disks.