8.53 V$ASM_DISK

V$ASM_DISK displays one row for every disk discovered by the Oracle Automatic Storage Management (Oracle ASM) instance, including disks that are not part of any disk group.

Column Datatype Description

GROUP_NUMBER

NUMBER

Number of the disk group containing the disk (foreign key to the V$ASM_DISKGROUP view)

DISK_NUMBER

NUMBER

Number assigned to the disk within its disk group

COMPOUND_INDEX

NUMBER

A 32-bit number consisting of a disk group number in the high-order 8 bits and a disk number in the low-order 24 bits (for efficient access to the view)

INCARNATION

NUMBER

Incarnation number for the disk

MOUNT_STATUS

VARCHAR2(7)

Per-instance status of the disk relative to group mounts:

  • MISSING - Oracle ASM metadata indicates that the disk is known to be part of the Oracle ASM disk group but no disk in the storage system was found with the indicated name

  • CLOSED - Disk is present in the storage system but is not being accessed by Oracle ASM

  • OPENED - Disk is present in the storage system and is being accessed by Oracle ASM. This is the normal state for disks in a database instance which are part of a disk group being actively used by the instance.

  • CACHED - Disk is present in the storage system and is part of a disk group being accessed by the Oracle ASM instance. This is the normal state for disks in an Oracle ASM instance which are part of a mounted disk group.

  • IGNORED - Disk is present in the system but is ignored by Oracle ASM because of one of the following:

    • The disk is detected by the system library but is ignored because an Oracle ASM library discovered the same disk

    • Oracle ASM has determined that the membership claimed by the disk header is no longer valid

  • CLOSING - Oracle ASM is in the process of closing this disk

HEADER_STATUS

VARCHAR2(12)

Per-instance status of the disk as seen by discovery:

  • UNKNOWN - Oracle ASM disk header has not been read

  • CANDIDATE - Disk is not part of a disk group and may be added to a disk group with the ALTER DISKGROUP statement

  • INCOMPATIBLE - Version number in the disk header is not compatible with the Oracle ASM software version

  • PROVISIONED - Disk is not part of a disk group and may be added to a disk group with the ALTER DISKGROUP statement. The PROVISIONED header status is different from the CANDIDATE header status in that PROVISIONED implies that an additional platform-specific action has been taken by an administrator to make the disk available for Oracle ASM.

  • MEMBER - Disk is a member of an existing disk group. No attempt should be made to add the disk to a different disk group. The ALTER DISKGROUP statement will reject such an addition unless overridden with the FORCE option.

  • FORMER - Disk was once part of a disk group but has been dropped cleanly from the group. It may be added to a new disk group with the ALTER DISKGROUP statement.

  • CONFLICT - Oracle ASM disk was not mounted due to a conflict

  • FOREIGN - Disk contains data created by an Oracle product other than Oracle ASM. This includes data files, logfiles, and OCR disks.

MODE_STATUS

VARCHAR2(7)

Global status about which kinds of I/O requests are allowed to the disk:

  • ONLINE - Disk is online and operating normally. Reads and writes are attempted when the disk is mounted. Reads are attempted as part of disk discovery.

  • OFFLINE - Disk is offline and access to data is not permitted. Reads and writes are not attempted. An offline disk remains logically part of its disk group.

  • SYNCING - Disk is offline for reads, but online for writes. Oracle ASM is resyncing stale data on the disk. See V$ASM_OPERATION to view resync progress.

STATE

VARCHAR2(8)

Global state of the disk with respect to the disk group:

  • UNKNOWN - Oracle ASM disk state is not known (typically the disk is not mounted)

  • NORMAL - Disk is online and operating normally

  • ADDING - Disk is being added to a disk group, and is pending validation by all instances that have the disk group mounted

  • DROPPING - Disk has been manually taken offline and space allocation or data access for the disk halts. Rebalancing will commence to relocate data off the disks to other disks in the disk group. Upon completion of the rebalance, the disk is expelled from the group.

  • HUNG - Disk drop operation cannot continue because there is insufficient space to relocate the data from the disk being dropped

  • FORCING - Disk is being removed from the disk group without attempting to offload its data. The data will be recovered from redundant copies, where possible.

REDUNDANCY

VARCHAR2(7)

Hardware redundancy of the disk:

  • UNKNOWN

  • UNPROT

  • MIRROR

  • PARITY

Note: This column is valid only if an ASMLIB is present that supports returning hardware redundancy information. This column is not related to the redundancy of the disk group of which the disk is a member.

LIBRARY

VARCHAR2(64)

Name of the library that discovered the disk

OS_MB

NUMBER

Size of the disk (in megabytes) as reported by the host operating system

TOTAL_MB

NUMBER

Total capacity of the disk (in megabytes)

FREE_MB

NUMBER

Unused capacity of the disk (in megabytes)

HOT_USED_MBFoot 1

NUMBER

Number of used megabytes in the hot region

COLD_USED_MBFoot 1

NUMBER

Number of used megabytes in the cold region

NAME

VARCHAR2(30)

Name of the disk

FAILGROUP

VARCHAR2(30)

Name of the failure group containing the disk

LABEL

VARCHAR2(31)

Disk label portion of the name returned by discovery

PATH

VARCHAR2(256)

Operating system path name portion of the name returned by discovery

UDID

VARCHAR2(64)

Unique Device ID portion of the name returned by discovery

PRODUCT

VARCHAR2(32)

Name of the manufacturer and the name of the product. All disks with the same product id will have the same performance and reliability characteristics.

CREATE_DATE

DATE

Date and time when the disk was added to the disk group

MOUNT_DATE

DATE

Date and time when the disk was mounted by the first instance

REPAIR_TIMER

NUMBER

Seconds remaining until the disk is automatically dropped (0 if not failed)

READS

NUMBER

Total number of I/O read requests for the disk

WRITES

NUMBER

Total number of I/O write requests for the disk

READ_ERRS

NUMBER

Total number of failed I/O read requests for the disk

WRITE_ERRS

NUMBER

Total number of failed I/O write requests for the disk

READ_TIMEOUT

NUMBER

Number of read I/Os that are timed out

WRITE_TIMEOUT

NUMBER

Number of write I/Os that are timed out

READ_TIME

NUMBER

Total I/O time (in seconds) for read requests for the disk if the TIMED_STATISTICS initialization parameter is set to true (0 if set to false)

WRITE_TIME

NUMBER

Total I/O time (in seconds) for write requests for the disk if the TIMED_STATISTICS initialization parameter is set to true (0 if set to false)

BYTES_READ

NUMBER

Total number of bytes read from the disk

BYTES_WRITTEN

NUMBER

Total number of bytes written to the disk

PREFERRED_READ

VARCHAR2(1)

Status of the preferred read failure group:

  • U - Disk group has no preferred read failure group

  • Y - Disk is a preferred read disk

  • N - Disk is not a preferred read disk

For a disk group with one or more preferred read failure groups, if the disk is in one of the preferred read failure groups, the value of this column is Y; otherwise it is N.

HASH_VALUE

NUMBER

A unique hash value for an Oracle ASM disk, computed using the Oracle ASM disk name (as specified by NAME column in v$asm_disk) and the Oracle ASM disk group name (as specified by NAME column in v$asm_diskgroup).

HOT_READSFoot 1

NUMBER

This column is not meaningful and its value is always 0

HOT_WRITESFoot 1

NUMBER

This column is not meaningful and its value is always 0

HOT_BYTES_READFoot 1

NUMBER

This column is not meaningful and its value is always 0

HOT_BYTES_WRITTENFoot 1

NUMBER

This column is not meaningful and its value is always 0

COLD_READSFoot 1

NUMBER

Number of reads from the disk

COLD_WRITESFoot 1

NUMBER

Number of writes to the disk

COLD_BYTES_READFoot 1

NUMBER

Number of bytes read from the disk

COLD_BYTES_WRITTENFoot 1

NUMBER

Number of bytes written to the disk

VOTING_FILE

VARCHAR2(1)

Indicates whether the disk contains a voting file (Y) or not (N)

SECTOR_SIZE

NUMBER

Physical block size (in bytes)

LOGICAL_SECTOR_SIZE

NUMBER

Shows the logical sector size value of the disk in bytes. This is the smallest possible I/O that can be done by the disk.

If the value of the LOGICAL_SECTOR_SIZE column is 512, while the value in the SECTOR_SIZE column is 4096, then the disk supports 512 sector size emulation. This means the disk can be used for both 512 native and 4096 native disk groups.

FAILGROUP_TYPE

VARCHAR2(7)

Type of the failure group:

  • REGULAR

  • QUORUM

CON_ID

NUMBER

The ID of the container to which the data pertains. Possible values include:

  • 0: This value is used for rows containing data that pertain to the entire CDB. This value is also used for rows in non-CDBs.

  • 1: This value is used for rows containing data that pertain to only the root

  • n: Where n is the applicable container ID for the rows containing data

For this view, the value is always 0.

THIN_PROVISION_CAPABLE

VARCHAR2(1)

Indicates whether the disk supports Storage Thin Provisioning (Y) or not (N)

DATA_INTEGRITY_CAPABLE

VARCHAR2(1)

Indicates whether the disk supports the Data Integrity feature (Y) or not (N)

SITE_NAME

VARCHAR2(30)

The name of the site to which the specific disk belongs

SITE_GUID

VARCHAR2(33)

The GUID for the site to which the specific disk belongs

FAILGROUP_LABEL

VARCHAR2(30)

This is the suggested name for the failure group to which the disk belongs, as returned by discovery

SITE_LABEL

VARCHAR2(30)

This is the suggested name for the site to which the disk belongs, as returned by discovery

SITE_STATUS

VARCHAR2(11)

This column is populated only for disks in Oracle ASM extended disk groups. The site status is computed after every Partnership and Status Table (PST) refresh or when the PST is read from disks into memory. The possible states include:

  • UNKNOWN: This is the state before any checks have been performed.

  • UNAVAILABLE: This is the state when all the disks in the site are offline.

  • COMPROMISED: The state when enough disks or PST copies are offline, such that the site can no longer provide data availability.

  • AVAILABLE: The state when there is enough redundancy within the site to provide data availability in case another site becomes compromised or unavailable.

Footnote 1 Intelligent Data Placement is desupported starting with Oracle Database 21c. As a result, the individual values for the HOT_USED_MB and COLD_USED_MB columns are not meaningful. However, the sum of the HOT_USED_MB and COLD_USED_MB values represents the total number of used megabytes on the disk. Also, the HOT_READS, HOT_WRITES, HOT_BYTES_READ, and HOT_BYTES_WRITTEN columns are no longer meaningful and always return 0, and the COLD_READS, COLD_WRITES, COLD_BYTES_READ, and COLD_BYTES_WRITTEN columns return statistics for the entire disk.

Note:

The GROUP_NUMBER and DISK_NUMBER columns will only be valid if the disk is part of a disk group which is currently mounted by the instance. Otherwise, GROUP_NUMBER will be 0, and DISK_NUMBER will be a unique value with respect to the other disks that also have a group number of 0.

Note:

In an Oracle Database instance, this view returns 0 rows when queried from a PDB.

See Also:

Oracle Automatic Storage Management Administrator's Guide for additional information about using views to display Oracle ASM information