This topic discusses how to create a disk group for data and a disk group for the fast recovery area.
The SQL statement in Example 4-1 creates a disk group named
data with normal redundancy consisting of two failure groups
controller2 with four disks in each failure group. The
data disk group is typically used to store database data files.
The example assumes that the
ASM_DISKSTRING initialization parameter is set to the '
/devices/*' string. Oracle ASM disk discovery identifies
diskb4 in the
In Example 4-1, the
NAME clauses enable you to explicitly assign names to the disks rather than the default system-generated names. The system-generated names are in the form
nnnn is the disk number for the disk in the disk group. For information about the disk name format when using Oracle ASM Filter Driver, refer to "Oracle ASM Filter Driver".
When creating the disk group in Example 4-1, the values of following disk group attributes were explicitly set:
Specifies the size of the allocation unit for the disk group. For information about allocation units, see "About Oracle ASM Allocation Units ".
You can view the value of the
AU_SIZE disk group attribute in the
ALLOCATION_UNIT_SIZE column of the
Determines the minimum software version for any Oracle ASM instance that uses a disk group. For information about the
COMPATIBLE.ASM attribute, see "COMPATIBLE.ASM".
Determines the minimum software version for any database instance that uses a disk group. For information about the
COMPATIBLE.RDBMS attribute, see "COMPATIBLE.RDBMS".
Determines whether the disk group can contain Oracle ADVM volumes. For information about the
COMPATIBLE.ADVM attribute, see "COMPATIBLE.ADVM".
In Example 4-2, the
fra disk group (typically created for the fast recovery area) is created with the default disk group attribute values. Names are not specified for the Oracle ASM disks and failure groups are not explicitly specified. This example assumes that
diskc9 are present in the
Example 4-1 Creating the DATA disk group
CREATE DISKGROUP data NORMAL REDUNDANCY FAILGROUP controller1 DISK '/devices/diska1' NAME diska1, '/devices/diska2' NAME diska2, '/devices/diska3' NAME diska3, '/devices/diska4' NAME diska4 FAILGROUP controller2 DISK '/devices/diskb1' NAME diskb1, '/devices/diskb2' NAME diskb2, '/devices/diskb3' NAME diskb3, '/devices/diskb4' NAME diskb4 ATTRIBUTE 'au_size'='4M', 'compatible.asm' = '11.2', 'compatible.rdbms' = '11.2', 'compatible.advm' = '11.2';
Example 4-2 Creating the FRA disk group
CREATE DISKGROUP fra NORMAL REDUNDANCY DISK '/devices/diskc*';