Advancing the disk group compatibility settings enables you to use the new Oracle ASM features that are available in a later release. For example, a disk group with the disk group compatibility attributes set to 12.1 can take advantage of Oracle ASM 12c Release 1 (12.1) features. See Table 4-3 for the features enabled for combinations of compatibility attribute settings.
The disk group compatibility feature also enables environments to interoperate when they use disk groups from both Oracle Database 10g and Oracle Database 11g instances. For example, disk group compatibility settings that are set to Oracle Database 10g Release 2 (10.2) enable an Oracle Database 10g Release 2 (10.2) client to access a disk group created with Oracle ASM 12c Release 1 (12.1).
The disk group attributes that determine compatibility are COMPATIBLE.ASM, COMPATIBLE.RDBMS. and COMPATIBLE.ADVM. The COMPATIBLE.ASM and COMPATIBLE.RDBMS attribute settings determine the minimum Oracle Database software version numbers that a system can use for Oracle ASM and the database instance types respectively. 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. The COMPATIBLE.ADVM attribute determines whether the Oracle ASM Dynamic Volume Manager feature can create a volume in a disk group.
When you create a disk group, you can specify the disk group compatibility attribute settings in the CREATE DISKGROUP SQL statement. The ALTER DISKGROUP SQL statement can update the compatible attribute settings for existing disk groups. See Table 4-2 for examples of valid combinations of compatible attribute settings.
The compatibility attributes are not set to zero releases, such as 11.0 or 12.0 or any value with all zeroes following the first dot.
You can set and update disk group attributes with the ASMCMD setattr command. For information about the ASMCMD setattr command, see "setattr".
The disk group compatibility settings determine whether your environment can use the latest Oracle ASM features.
The disk group compatibility settings can only be advanced; you cannot revert to a lower compatibility setting. See "Reverting Disk Group Compatibility".
The COMPATIBLE.ASM attribute must be advanced before advancing other disk group compatibility attributes and its value must be greater than or equal to the value of other disk group compatibility attributes.