Check the compatibility of ASM diskgroup in Oracle

Oracle 11g introduce the ASM Attributes which help in finding ASM and Database software version to access diskgroups.

Compatibile.ASM = Defines the minimum version of ASM software instance that can access disk group.
Compatibile.RDBMS = Defines the minimum COMPATIBLE parameter setting for database instance that can access diskgroup.

For example, if the Oracle ASM compatibility setting is 12.1, and RDBMS compatibility is set to 11.2, then the Oracle ASM software version must be at least 12.1, and the Oracle Database client software version must be at least 11.2.

Note:
1. Value of COMPATIBLE.ASM must always be greater than or equal to the value of COMPATIBLE.RDBMS.
2. Compatibility versions of a diskgroup only be increased,it’s not decreased. If you increased it and want to decrease it then you need to drop and create it again.

Check the compatibility of a ASM diskgroup

SELECT name AS diskgroup, substr(compatibility,1,12) AS asm_compat,
substr(database_compatibility,1,12) AS db_compat FROM V$ASM_DISKGROUP;

DISKGROUP ASM_COMPAT DB_COMPAT
--------- ---------- ----------
DATA      18.0.0.0.0 18.0.0.0.0
DATA1     18.0.0.0.0 18.0.0.0.0

Check the ASM attribute

column value for a20
column name for a20
SELECT group_number, name, value FROM v$asm_attribute ORDER BY group_number, name;

NUMBER       NAME                 VALUE
------------ -------------------- --------------------
           1 au_size              1048576
           1 compatible.asm       11.1.0.0.0
           1 compatible.rdbms     11.1
           1 disk_repair_time     3.6h

Create diskgroup defines tha attribute

CREATE DISKGROUP data01 DISK '/dev/raw/disk*'
ATTRIBUTE 'compatible.rdbms' = '11.1', 'compatible.asm' = '11.1';


Alter command only used to increased value

ALTER DISKGROUP data01 SET ATTRIBUTE 'compatible.asm' = '11.1';
ALTER DISKGROUP data01 SET ATTRIBUTE 'compatible.rdbms' = '11.1';