Summary of Disk Group Attributes

This attribute configures Oracle ASM File Access Control and can only be set when altering a disk group.

For information about the ACCESS_CONTROL.ENABLED attribute, see "Setting Disk Group Attributes for Oracle ASM File Access Control".

This attribute configures Oracle ASM File Access Control and can only be set when altering a disk group.

For information about the ACCESS_CONTROL.UMASK attribute, see "Setting Disk Group Attributes for Oracle ASM File Access Control".

This attribute specifies allocation unit (AU) size and can only be set when creating a disk group. Example 4-1 shows how the AU_SIZE is specified with the CREATE DISKGROUP SQL statement.

For information about allocation units, refer to "About Oracle ASM Allocation Units ".

This attribute is only applicable to the configuration of Oracle Exadata storage.

This attribute is only applicable to the configuration of Oracle Exadata storage.

This attribute specifies the Oracle ASM compatibility level of a disk group. Compatibility attributes can be set when the disk group is created and advanced when a disk group is altered, but compatibility attributes cannot be reversed. For information about the COMPATIBLE.ASM attribute, see "COMPATIBLE.ASM".

This attribute specifies the database compatibility level of a disk group. Compatibility attributes can be set when the disk group is created and advanced when a disk group is altered, but compatibility attributes cannot be reversed. For information about the COMPATIBLE.RDBMS attribute, see "COMPATIBLE.RDBMS".

This attribute specifies the Oracle Automatic Storage Management Cluster File System (Oracle ACFS) and Oracle ASM Dynamic Volume Manager (Oracle ADVM) compatibility level of a disk group. Compatibility attributes can be set when the disk group is created and advanced when a disk group is altered, but compatibility attributes cannot be reversed. For information about the COMPATIBLE.ADVM attribute, see "COMPATIBLE.ADVM" and "Overview of Oracle ASM Dynamic Volume Manager".

This attributes enables or disables content checking when performing data copy operations for rebalancing a disk group. The attribute value can be set to true or false.

The content checking can include Hardware Assisted Resilient Data (HARD) checks on user data, validation of file types from the file directory against the block contents and file directory information, and mirror side comparison.

When the attribute is set to true, logical content checking is enabled for all rebalance operations.

For information about disk group rebalancing, refer to "Manually Rebalancing Disk Groups" and "Tuning Rebalance Operations".

This attribute identifies the disk group type: data, recovery, or system. The type value determines where Oracle ASM places the nearest neighbor disk in the failure group where Oracle ASM mirrors copies of the data. Oracle ASM uses this attribute value to make it less likely that a double failure in the storage medium causes disk groups of different content types to become unavailable. Specifying this attribute enables Oracle ASM to better deploy all disk groups in the available storage.

The default value is data which specifies a distance of 1 to the nearest neighbor disk. A value of recovery specifies a distance of 3 to the nearest neighbor disk and a value of system specifies a distance of 5.

The attribute can be specified when creating or altering a disk group. If CONTENT.TYPE attribute is set or changed using ALTER DISKGROUP, then the new configuration does not take effect until a disk group rebalance is explicitly run.

The CONTENT.TYPE attribute is only valid for disk groups that are set to normal or high redundancy. The COMPATIBLE.ASM attribute must be set to 11.2.0.3 or higher to enable the CONTENT.TYPE attribute for the disk group.

This attribute can be set with ASMCMD mkdg or SQL CREATE and ALTER DISKGROUP statements.

For example:

SQL> CREATE DISKGROUP data NORMAL REDUNDANCY
        FAILGROUP controller1 DISK
        '/devices/diska1' NAME diska1,
...
        ATTRIBUTE 
        'compatible.asm' = '12.1.0.1', 
        'content.type' = 'recovery',
...

SQL> ALTER DISKGROUP data SET ATTRIBUTE 'content.type' = 'data';

This attribute is primarily intended for use with Oracle Exadata storage.

For information about disk resync, see "Oracle ASM Fast Mirror Resync".

This attribute specifies the time interval to repair a disk and bring it back online. before initiating the drop operation. This attribute can only be set when altering a disk group and is only applicable to normal and high redundancy disk groups.

For information about disk repair time, see "Oracle ASM Fast Mirror Resync".

This attribute specifies a default repair time for the failure groups in the disk group. The failure group repair time is used if Oracle ASM determines that an entire failure group has failed. The default value is 24 hours (24h). If there is a repair time specified for a disk, such as with the DROP AFTER clause of the SQL ALTER DISKGROUP OFFLINE DISK statement, that disk repair time overrides the failure group repair time.

This attribute can only be set when altering a disk group and is only applicable to normal and high redundancy disk groups.

For information about failure group repair time, see "Oracle ASM Fast Mirror Resync".

These attributes are used to configure Oracle Exadata storage.

This disk group attribute tracks the replication status of a disk group. When the Oracle ASM compatibility of a disk group is advanced to 12.1 or higher, the physical metadata of each disk is replicated. This metadata includes the disk header, free space table blocks, and allocation table blocks. The replication is performed online asynchronously. This attribute value is set to true by Oracle ASM if the physical metadata of every disk in the disk group has been replicated.

This disk group attribute is only defined in a disk group with the Oracle ASM disk group compatibility (COMPATIBLE.ASM) set to 12.1 and higher. This attribute is read-only and is intended for information only. A user cannot set or change its value. The values are either true or false.

This attribute specifies the sector size for disks in a disk group and can only be set when creating a disk group.

For information about the SECTOR_SIZE attribute, see "Specifying the Sector Size for Drives".

This disk group attribute specifies the type of the disks in the disk group. The possible values are AXIOM, ZFSSA, and OTHER. If the attribute is set to AXIOM or ZFSSA, then all disks in the disk group must be of that type. If the attribute is set to OTHER, then any types of disks can be in the disk group.

If the STORAGE.TYPE disk group attribute is set to AXIOM or ZFSSA, then functionality for Hybrid Columnar Compression (HCC) can be enabled for Pillar Axiom or ZFS storage.

To set the STORAGE.TYPE attribute, the COMPATIBLE.ASM and COMPATIBLE.RDBMS disk group attributes must be set to 11.2.0.3 or higher. For maximum support with ZFS storage, set the COMPATIBLE.ASM and COMPATIBLE.RDBMS disk group attributes to 11.2.0.4 or higher. For information about disk group compatibility attributes, refer to "Disk Group Compatibility".

The STORAGE.TYPE attribute can be set when creating a disk group or when altering a disk group. The attribute cannot be set when clients are connected to the disk group. For example, the attribute cannot be set when an Oracle ADVM volume is enabled on the disk group.

The attribute is not visible in the V$ASM_ATTRIBUTE view or with the ASMCMD lsattr command until the attribute has been set.

This attribute enables or disables the functionality to discard unused storage space after a disk group rebalance is completed. The attribute value can be true or false. The default value is false.

Storage vendor products that support thin provisioning have the capability to reuse the discarded storage space for a more efficient overall physical storage utilization.

For information about disk group rebalancing, refer to "Tuning Rebalance Operations".