1.3.2.2.1 Oracle ASM Disk Groups

An Oracle Automatic Storage Management (Oracle ASM) disk group is the primary storage abstraction within Oracle ASM, and is composed of one or more grid disks.

Oracle Exadata Storage Server grid disks appear to Oracle ASM as individual disks available for membership in Oracle ASM disk groups. Whenever possible, grid disk names should correspond closely with Oracle ASM disk group names to assist in problem diagnosis between Oracle ASM and Oracle Exadata System Software.

Typically, Oracle Exadata is configured with the following Oracle ASM disk groups:

• DATA is the primary data disk group.

• RECO is the primary recovery disk group, which contains the Oracle Database Fast Recovery Area (FRA).

• SPARSE is an optionally configured sparse disk group that is required to support Exadata snapshots.

• XTND is the default name for the disk group that is used to collect storage from Exadata XT (Extended) storage servers.

• DBFS is the system disk group that is typically configured on systems prior to Exadata X7. The DBFS disk group is primarily used to store the shared Oracle Clusterware files (Oracle Cluster Registry and voting disks) and provide some space to host Oracle Database File System (DBFS). This disk group is not configured on Exadata X7, and later, systems.

To take advantage of Oracle Exadata System Software features, such as predicate processing offload, the disk groups must contain only Oracle Exadata Storage Server grid disks, the tables must be fully inside these disk groups, and the group should have cell.smart_scan_capable attribute set to TRUE.

Note:

The Oracle Database and Oracle Grid Infrastructure software must be release 12.1.0.2.0 BP3 or later when using sparse grid disks.